阅读说明：本技术 根据基本元件的库构建符合规范的多频带天线布置 (Building a specification compliant multi-band antenna arrangement from a library of base elements ) 是由 J-P·库佩 于 2019-06-27 设计创作，主要内容包括：本发明公开了一种天线布置,该天线布置被设计为基于成本函数匹配或接近规范,该规范包括多个预定义的频率的列表,并且可能包括处于匹配级别的预定义的带宽的列表。使用多个预定义的元件来设计天线布置,这些预定义的元件包括被定义为主要干线的主要导电元件以及从干线、分支或叶子选择的次要导电元件的组合。主要导电元件和次要导电元件由设计参数定义,该设计参数包括电纳,其是几何形状、外形规格、主要维度、次要导电元件相对于主要导电元件的定向以及次要导电元件在主要导电元件上的位置的函数。还可以定义天线布置以匹配预定义的外形规格。(The invention discloses an antenna arrangement designed to match or approach a specification based on a cost function, the specification comprising a list of a plurality of predefined frequencies, and possibly a list of predefined bandwidths at the matching level. The antenna arrangement is designed using a number of predefined elements including a combination of a primary conductive element defined as the primary trunk and a secondary conductive element selected from the trunk, branch or leaf. The primary and secondary conductive elements are defined by design parameters including susceptance, which is a function of geometry, form factor, primary dimension, orientation of the secondary conductive element relative to the primary conductive element, and location of the secondary conductive element on the primary conductive element. The antenna arrangement may also be defined to match a predefined form factor.)

1. An antenna arrangement (200), comprising:

-a main conductive element (211) having defined geometrical parameters, the main conductive element having a proximal end and a distal end, the proximal end being connected at a feed line (210), the distal end being an open circuit position, the main conductive element defining a first plurality of resonance frequencies;

-one or more secondary conductive elements (212, 221, 231), each secondary conductive element having defined geometrical parameters, a proximal end connected at a feed connection on the primary conductive element, and a distal end being an open circuit position and defining an orientation relative to the primary conductive element, the one or more secondary conductive elements generating a second plurality of resonant frequencies;

wherein the frequencies in the second plurality of resonant frequencies each satisfy a resonant condition at the feedline, the resonant condition being determined by a sequence of combinations of an input susceptance of a segment of the primary conductive element and an input susceptance of one of the one or more secondary conductive elements, each combination being generated on the primary conductive element at the feed connection of the one or more secondary conductive elements, the segment of the primary conductive element connecting one of its distal end or a feed connection of another of the one or more secondary conductive elements to the one of the one or more secondary elements, the sequence starting from the distal end of the primary conductive element and ending at its proximal end.

2. An antenna arrangement as claimed in claim 1, wherein the second plurality of resonant frequencies is derived from the first plurality of resonant frequencies by one or more of: offsetting one or more frequency values; amplifying a bandwidth of one or more of the plurality of resonant frequencies; or to add one or more new resonance frequencies.

3. The antenna arrangement according to one of claims 1-2, wherein the input susceptance of a segment of the primary conductive element is determined by the defined geometric parameter of the primary conductive element.

4. The antenna arrangement according to one of claims 1-3, wherein the input susceptance of each of the one or more secondary conductive elements depends on the defined geometric parameter of the each of the one or more secondary conductive elements and on an orientation of the each secondary conductive element relative to the primary conductive element.

5. The antenna arrangement according to one of claims 1-4, wherein the defined geometric parameters of the primary conductive element and of each of one or more secondary elements comprise a geometry, a form factor and a primary dimension.

6. The antenna arrangement according to one of claims 1-5, wherein a major dimension of one of the one or more secondary conductive elements is below a quarter of a wavelength corresponding to a highest value of the second plurality of resonance frequencies of the antenna arrangement, the addition of the one or more secondary conductive elements having the effect of shifting one or more of the first plurality of resonance frequencies of the antenna arrangement.

7. The antenna arrangement according to one of claims 1-5, wherein a major dimension of one of the one or more secondary conductive elements is higher than a quarter of a wavelength corresponding to a highest value of the second plurality of resonance frequencies of the antenna arrangement and lower than a quarter of a wavelength corresponding to a lowest value of the second plurality of resonance frequencies of the antenna arrangement.

8. An antenna arrangement as claimed in claim 7, wherein adding the one or more secondary conductive elements has the effect of adding one or more potential new resonant frequencies to the first plurality of resonant frequencies of the antenna arrangement, the new resonant frequencies having values between a value corresponding to a wavelength equal to one quarter of the major dimension of the one or more secondary conductive elements and the highest of the second plurality of resonant frequencies.

9. An antenna arrangement as claimed in claim 8, wherein one or more of the potential new resonant frequencies is a new resonant frequency if it is sufficiently separated from all frequency values of the first plurality of resonant frequencies.

10. An antenna arrangement as claimed in claim 8, wherein adding the one of the one or more secondary conductive elements has the effect of shifting one or more of the first plurality of resonant frequencies of the antenna arrangement between the lowest and highest of the second plurality of resonant frequencies when the one of the one or more secondary conductive elements has a feed connection that is not located at the feed line.

11. The antenna arrangement according to one of claims 1-10, further comprising one or more third conductive elements (222, 232, 233, 234), each having defined geometrical parameters, a proximal end connected at a feed connection on one of the one or more secondary conductive elements (212, 221), and a distal end being an open circuit position and defining an orientation with respect to the one of the one or more secondary conductive elements.

12. An antenna arrangement as claimed in claim 11, further comprising one or more fourth conductive elements (235), each fourth conductive element having defined geometric parameters, a proximal end connected at a feed connection on one (222) of the one or more third conductive elements, and a distal end which is an open circuit position and defines an orientation relative to the one of the one or more third conductive elements.

13. A method of designing an antenna arrangement, comprising:

-defining a main conductive element having determined geometrical parameters, the main conductive element having a proximal end and a distal end, the proximal end being connected at a feed line, the distal end being an open circuit position, the main conductive element defining a first plurality of resonance frequencies;

-defining one or more secondary conductive elements, each secondary conductive element having determined geometrical parameters, a proximal end connected at a feed connection on the primary conductive element, and a distal end being an open circuit position and defining an orientation with respect to the primary conductive element, the one or more secondary conductive elements generating a second plurality of resonance frequencies;

wherein the geometric parameters of the primary conductive element and the geometric parameters of the one or more secondary conductive elements are determined in such a way that: frequencies in the second plurality of resonant frequencies each satisfy a resonant condition at the feedline, the resonant condition being determined by a sequence of combinations of an input susceptance of a segment of the primary conductive element and an input susceptance of one of the one or more secondary conductive elements, each combination being generated on the primary conductive element at the feed connection of the one or more secondary conductive elements, the segment of the primary conductive element connecting one of its distal end or a feed connection of another of the one or more secondary conductive elements to the one of the one or more secondary elements, the sequence starting from the distal end of the primary conductive element and ending at its proximal end.

14. The method of claim 13, wherein the one or more secondary conductive elements are iteratively added to the primary conductive element at defined locations so as to match a specification of the antenna arrangement including a second plurality of predefined frequencies.

15. The method of claim 14, wherein the one or more secondary conductive elements added to match the specification of the antenna arrangement are further defined as: matching a specified bandwidth for at least one or more frequencies of the second plurality of predefined frequencies.

16. The method of one of claims 13-15, wherein the one or more secondary conductive elements added to match a specification are further defined as: matching the form factor of the antenna arrangement.

17. The method according to one of claims 13-16, wherein the one or more secondary elements are derived from a database of predefined elements.

18. The method of claim 17, wherein the predefined elements have been generated by using one or more of a Smith chart-based graphical calculation, an analytical calculation, a simulation tool, or a model.

19. The method according to one of claims 13-18, wherein the matching to the specification is performed by using one or more of graphical calculations, analytical calculations, simulation tools or models based on Smith charts.

20. The method of claim 19, wherein the matching to the specification is further performed by optimizing a cost function.

Technical Field

The present invention relates to an antenna arrangement having multiple frequency modes in the VHF, UHF, S, C, X or higher frequency bands. More precisely, an antenna arrangement with a compact form factor can be designed according to the invention to match the specifications and constructed from a library of basic elements, such as minor trunks (trunk), branches and major parts of leaves. Thanks to the invention, a designer of such an antenna arrangement can be provided with tools and libraries that greatly improve his/her efficiency in antenna development.

Background

Terminals or smart phones on airplanes, ships, trains, trucks, cars or carried by pedestrians need to be connected while moving. Various objects on a vehicle or located at a manufacturing plant, office, warehouse, storage facility, retail location, hospital, sports arena, or home are connected to the internet of things (IoT): tags for locating and identifying objects in inventory or for people to enter or exit restricted areas; a device for monitoring physical activity or health parameters of a user thereof; sensors for capturing environmental parameters (pollutant concentration, hydrometry, wind speed, etc.); actuators for remote control and command of various devices, or more generally any type of electronic equipment that can be part of a command, control, communication and intelligence system, for example programmed to: capture/process signals/data; transmitting the signal/data to another electronic device or a server; processing the data using processing logic that implements artificial intelligence or knowledge-based reasoning; and return information or activate commands to be implemented by the actuator.

RF communication is more versatile than fixed line communication in connecting these types of objects or platforms. Therefore, radio frequency T/R modules will become more and more popular in professional and consumer applications. Multiple T/R modules may be implemented on the same device. By way of example, a smartphone typically includes a cellular communication T/R module, a Wi-Fi/Bluetooth T/R module, a GNSS (from a Global navigation satellite System) or a GNSS) A receiver of satellite positioning signals. Wi-Fi^TM、Bluetooth^TMAnd 3G or 4G cellular communication in the 2.5GHz band (S-band). GNSS receivers typically operate in the 1.5GHz band (L-band). Radio Frequency Identification (RFID) tags operate in the 900MHz band (UHF) or lower. Near Field Communication (NFC) tags operate in the 13MHz band (HF) at very short distances (about 10 cm).

A good compromise for IoT connections appears to be in the VHF band (30MHz to 300MHz) or UHF band (300MHz to 3GHz) to obtain sufficient available bandwidth and range, good resilience to multipath reflections, and low power budget.

The problem to be solved with the design of T/R modules at these frequency bands is an antenna with a form factor that is compact enough to fit the connected object. Conventional monopole-type omnidirectional antennas suitable for the VHF band are between 25cm and 2.5m (λ/4) in length. A solution to this problem is provided, inter alia, by PCT application publication No. WO2015007746, which has the same inventor as the present application and is commonly assigned to the applicant of the present application. This application discloses an antenna arrangement of the plug type (bung type), wherein a plurality of antenna elements are combined such that the ratio between the maximum dimension of the arrangement and the wavelength may be much lower than one tenth of the wavelength, even lower than one twentieth of the wavelength, or in some embodiments lower than one fiftieth of the wavelength. To achieve such results, the antenna elements that control the basic mode of the antenna are wound in a 3D form factor (e.g., helical) such that their outer dimensions are reduced relative to their length.

However, it is also desirable that the connected devices be compatible with terminals that communicate using Wi-Fi or bluetooth bands and protocols. In this use case, some stages of the T/R module must be compatible with the VHF band and the S-band. If a GNSS receiver is added, T/R capacity in the L-band is also required. This means that the antenna arrangement of such a device should be able to communicate simultaneously or sequentially in different frequency bands. Adding as many antennas as bands is expensive in terms of form factor, power budget and materials. This presents another challenging problem to antenna design. Some solutions for base station antennas are disclosed by PCT applications with publication numbers WO2001/22528 and WO 2003/34544. But these solutions do not operate in the VHF band and do not provide a sufficiently compact arrangement in these bands.

The applicant of the present application has already filed a european patent application with publication number EP3285333, which has the same inventor as the present application. The present application discloses a "bonsai" (bonsai) antenna arrangement, i.e. an antenna arrangement comprising: a first conductive element configured to radiate above a defined electromagnetic radiation frequency; one or more additional (or secondary) conductive elements located at or near one or more locations defined by the location of a node of current according to a harmonic of the electromagnetic radiation (i.e., a zero current location or an Open Circuit (OC) location).

The potted landscape antenna arrangement disclosed in said patent application provides a certain flexibility to adjust the radiation frequency of the antenna near the higher order modes of the "trunk" antenna, thanks to the "leaves" placed at selected points of the trunk by the designer of the antenna arrangement. But this flexibility is constrained by certain limitations. It is worth noting that in practice the number of frequencies that can be tuned on the same trunk should be limited to four (the fundamental mode plus the three first higher order modes) to avoid electromagnetic coupling between leaves added to the trunk. Also, the length of the leaves should be kept a fraction of the length of the main line to avoid interference with other modes, thereby limiting the frequency offset to a fraction of the value of the radiation frequency of each mode. It is therefore not possible to realize any kind of selected frequency on an antenna arrangement of the type disclosed by this first patent application.

Some limitations of this prior art have been overcome to some extent by providing the main trunk with additional secondary trunks and/or branches to increase the number of resonant frequencies of the antenna arrangement and to broaden the frequency domain of its use, as disclosed in european patent application publication No. EP2017/306929.5, which has the same inventor and the same applicant as the present application.

Moreover, the first application does not disclose how to control the bandwidth around the resonance frequency. This drawback has been overcome to some extent by providing the main rail at a controlled location with additional further resonant elements to form a resonant structure of higher order than the structure at the frequency of one of the selected harmonics of the electromagnetic radiation of the main rail, as disclosed in european patent application publication No. EP2016/306768.9, having the same inventor and the same applicant as the present application.

These three patent applications disclose design methods associated with their disclosed antenna arrangements. There remains a need for a bonsai-type antenna arrangement that can be simply and quickly designed to match typical specifications, and then build the design from a library of basic components using design tools available to those of ordinary skill in the antenna design.

The present patent application overcomes these limitations to a large extent.

Disclosure of Invention

The present invention meets this need by providing an antenna arrangement built from primary and secondary elements that can be derived from a library of trunks, branches and/or leaves that are configurable and can be assembled according to a set of design rules based on a number of design parameters (e.g., their electromagnetic susceptances that match the desired specifications in terms of resonant frequency, bandwidth and form factor).

More specifically, the present invention discloses an antenna arrangement comprising: a primary conductive element having defined geometric parameters, the primary conductive element having a proximal end and a distal end, the proximal end being connected at the feed line (210), the distal end being an open circuit location, the primary conductive element defining a first plurality of resonant frequencies; one or more secondary conductive elements, each secondary conductive element having defined geometric parameters, a proximal end connected at a feed connection on the primary conductive element, and a distal end that is an open circuit position and defines an orientation relative to the primary conductive element, the one or more secondary conductive elements generating a second plurality of resonant frequencies; wherein the frequencies in the second plurality of resonant frequencies each satisfy a resonant condition at the feedline, the resonant condition being determined by a sequence of combinations of the input susceptance of the segment of the primary conductive element and the input susceptance of one of the one or more secondary conductive elements, each combination being generated on the primary conductive element at a feed connection of said one of the one or more secondary conductive elements, the segment of the primary conductive element connecting one of its distal end or a feed connection of another of the one or more secondary conductive elements to one of the one or more secondary elements, the sequence starting from the distal end of the primary conductive element and ending at its proximal end.

Advantageously, the second plurality of resonant frequencies is derived from the first plurality of resonant frequencies by one or more of: offsetting one or more frequency values; amplifying a bandwidth of one or more of the plurality of resonant frequencies; or to add one or more new resonance frequencies.

Advantageously, the input susceptance of the segment of the primary conductive element is determined by a defined geometric parameter of said primary conductive element.

Advantageously, the input susceptance of each of the one or more secondary conductive elements is dependent on a defined geometric parameter of said each of the one or more secondary conductive elements and on an orientation of said each secondary conductive element relative to the primary conductive element.

Advantageously, the defined geometric parameters of the primary conductive element and of each of the one or more secondary elements comprise a geometry, a form factor and a primary dimension.

Advantageously, the major dimension of one of the one or more secondary conductive elements is lower than a quarter of the wavelength corresponding to the highest of the second plurality of resonant frequencies of the antenna arrangement, the addition of the one or more secondary conductive elements having the effect of shifting one or more of the first plurality of resonant frequencies of the antenna arrangement.

Advantageously, the major dimension of one of the one or more secondary conductive elements is higher than a quarter of the wavelength corresponding to the highest value of the second plurality of resonant frequencies of the antenna arrangement and lower than a quarter of the wavelength corresponding to the lowest value of the second plurality of resonant frequencies of the antenna arrangement.

Advantageously, the addition of one or more secondary conductive elements has the effect of adding one or more potential new resonant frequencies to the first plurality of resonant frequencies of the antenna arrangement, the new resonant frequencies having a value between a value corresponding to a wavelength equal to one quarter of the major dimension of said one of the one or more secondary conductive elements and the highest of the second plurality of resonant frequencies.

Advantageously, one or more of the potential new resonant frequencies is a new resonant frequency if it is sufficiently separated from all of the frequency values of the first plurality of resonant frequencies.

Advantageously, when one of the one or more secondary conductive elements has a feed connection that is not located at the feed line, adding one of the one or more secondary conductive elements has the effect of shifting one or more resonant frequencies of the first plurality of resonant frequencies of the antenna arrangement between the lowest value of the second plurality of resonant frequencies and a frequency value corresponding to a wavelength equal to one quarter of the major dimension of said one of the one or more secondary conductive elements.

Advantageously, the input susceptance of one of the one or more secondary conductive elements is equal to the characteristic admittance of the equivalent monopole antenna multiplied by the tangent of a coefficient multiplied by the equivalent length of the one or more secondary conductive elements, the coefficient being equal to 2 π f/c, where f is one of the plurality of resonant frequencies and c is the speed of light.

Advantageously, the distance of one of the one or more secondary conductive elements at the distal end of the primary conductive elementAt a distance from the proximal end of the main conductive elementHaving a feed connection, the input susceptance of the one secondary conductive element being equal to the characteristic admittance of the equivalent monopole antenna multiplied by the cotangent of the coefficientTangent to coefficient multiplied byThe coefficient is equal to 2 pi f/c, where f is one of the plurality of resonant frequencies, and c is the speed of light.

Advantageously, the distance of one of the one or more secondary conductive elements at the distal end of the primary conductive elementAt a distance from the proximal end of the main conductive elementHaving a feed connection, the antenna arrangement further comprising a further secondary conductive element at a feed connection distance from one of the one or more secondary conductive elementsAt and distance from the feeder lineHaving a feed connection, the input susceptance of the further secondary conductive element being equal to the characteristic admittance of the equivalent monopole antenna multiplied by the cotangent of the coefficientTangent to coefficient multiplied byAnd is equivalent to one of the one or more secondary conductive elementsA difference between a sum of lengths of secondary conductive elements in parallel with a segment of the feed connection connecting the distal end of the primary conductive element to one of the one or more secondary conductive elements, the coefficient being equal to 2 π f/c, where f is one of the plurality of resonant frequencies and c is the speed of light.

Advantageously, the antenna arrangement of the present invention further comprises one or more third conductive elements, each third conductive element having defined geometric parameters, a proximal end connected at a feed connection on one of the one or more secondary conductive elements and a distal end which is an open circuit position and defines an orientation relative to the one of the one or more secondary conductive elements.

Advantageously, the antenna arrangement of the present invention further comprises one or more fourth conductive elements, each having defined geometric parameters, a proximal end connected at a feed connection on one of the one or more third conductive elements and a distal end which is an open circuit position and defines an orientation relative to one of the one or more third conductive elements.

Advantageously, the antenna device of the present invention is tuned to radiate in two or more frequency bands including one or more of an ISM band, a Wi-Fi band, a bluetooth band, a 3G band, an LTE band and a 5G band.

The invention also discloses a method for designing the antenna arrangement, which comprises the following steps: defining a primary conductive element having defined geometric parameters, the primary conductive element having a proximal end and a distal end, the proximal end being connected at the feed line and the distal end being an open circuit location, the primary conductive element defining a first plurality of resonant frequencies; defining one or more secondary conductive elements, each secondary conductive element having a determined geometric parameter, a proximal end connected at a feed connection on the primary conductive element, and a distal end, the distal end being an open circuit position and defining an orientation relative to the primary conductive element, the one or more secondary conductive elements generating a second plurality of resonant frequencies; wherein the geometric parameters of the primary conductive element and the one or more secondary conductive elements are determined in such a way that: the frequencies in the second plurality of resonant frequencies each satisfy a resonant condition at the feedline, the resonant condition being determined by a sequence of combinations of the input susceptances of the segment of the primary conductive element and the input susceptance of one of the one or more secondary conductive elements, each combination being generated on the primary conductive element at a feed connection of said one of the one or more secondary conductive elements, the segment of the primary conductive element connecting one of its distal end or a feed connection of another of the one or more secondary conductive elements to one of the one or more secondary elements, the sequence starting at the distal end of the primary conductive element and ending at its proximal end.

Advantageously, the one or more secondary conductive elements are iteratively added to the primary conductive element at defined locations so as to match a specification of an antenna arrangement comprising a second plurality of predefined frequencies.

Advantageously, the one or more secondary conductive elements added to match the specification of the antenna arrangement are further defined as: matching the specified bandwidth for at least one or more frequencies of a second plurality of predefined frequencies.

Advantageously, the one or more secondary conductive elements added to match the specification are further defined as: matching the form factor of the antenna arrangement.

Advantageously, the one or more secondary elements are derived from a database of predefined elements.

Advantageously, the predefined elements have been generated by using one or more of graphical calculations, analytical calculations, simulation tools or models based on Smith charts.

Advantageously, the matching to the specification is performed by using one or more of graphical calculations, analytical calculations, simulation tools or models based on Smith charts.

Advantageously, the matching to the specification is also performed by optimizing a cost function.

The antenna arrangement of the present invention provides the advantages of: a plurality of resonance frequencies with controlled values and controlled bandwidths are provided over a very wide frequency domain.

The antenna arrangement of the present invention may be compact, allowing it to be integrated in a small volume or reduced surface.

The antenna arrangement of the present invention is advantageously simple to design, especially when tuning at least two (but possibly more) radiation frequencies to a desired value, so that the relative positions of the first and second primary conductive elements and the secondary conductive element (or "leaf") have an electromagnetic effect on its electrical performance, taking into account the effects of the environment of the antenna arrangement, especially the effects of the ground plane.

The antenna arrangement of the present invention is easy to manufacture and therefore has a very low cost.

Furthermore, the antenna arrangement of the present invention is very easy to connect to an RF Printed Circuit Board (PCB) in either an orthogonal configuration or a coplanar configuration.

In some alternative embodiments, the bandwidth of the fundamental radiation frequency or higher order modes may be controlled to ensure a minimum quality of service for transmitting video or other content requiring high throughput at these controlled frequencies, taking into account the target matching level.

According to the present invention, a number of design tools are provided that allow for finding possible design parameters that match the specification in a graphical, analytical or numerical manner (or using a combination of the three).

Drawings

The invention and its advantages will be better understood by reading the following detailed description of specific embodiments, given by way of non-limiting example only, with reference to the accompanying drawings, in which:

figures 1a and 1b schematically show the specifications of the antennas currently used;

figure 2 shows an antenna arrangement constructed from a plurality of antenna elements according to some embodiments of the present invention;

3a, 3b, 3c, 3d and 3e illustrate different types of antenna elements according to some embodiments of the invention and some of its use cases;

4a, 4b, 4c, 4d, 4e, 4f and 4g show examples of differently shaped antenna elements according to some embodiments of the present invention;

5a, 5b, 5c and 5d illustrate examples of different form factor leaf antenna elements according to some embodiments of the present invention;

figures 5e, 5f, 5g and 5h illustrate examples of different form factor trunk/branch antenna elements according to some embodiments of the present invention;

6a, 6b, 6c, 6d, 6e, 6f and 6g show examples of assemblies of antenna elements according to some embodiments of the invention;

figures 7a, 7b, 7c, 7d, 7e and 7f show examples of assemblies of differently shaped antenna elements according to some embodiments of the present invention;

fig. 8 is a flow chart illustrating a design method of an antenna arrangement according to some embodiments of the invention;

fig. 9 is another flow chart illustrating a design method of an antenna arrangement according to some embodiments of the invention;

10a, 10c, 10e and 10g show examples of assemblies of antenna elements according to some embodiments of the invention, and 10b, 10d, 10f and 10h show the frequency responses of the responses of these assemblies;

11a, 11c and 11e show the distribution of the currents and voltages of the fundamental, the first higher and the second higher resonance modes of the monopole antenna, and 11b, 11d and 11f show the calculation of the input admittance of the antenna arrangement at each of these harmonics on the Smith chart, respectively;

12a, 12b and 12c show the calculation of the equivalent physical length of a leaf, and 12d, 12e and 12f show the effect of a leaf located on a main line on the fundamental resonance mode, the first higher resonance mode and the second higher resonance mode of the main line, respectively;

figure 13a shows two leaves located on a trunk; fig. 13b and 13c, 13d and 13e, and 13f and 13g respectively show the configuration of the antenna arrangement of fig. 13a and the calculation of its input admittance using the Smith chart.

Detailed Description

Fig. 1a and 1b schematically show the specifications of the antenna.

A problem to be solved by designers of antenna arrangements is to define various elements of the antenna arrangement that allow matching performance criteria of technical specifications. Typically, the performance criteria will include:

center frequency in a defined range [ f_min,f_max]N transmit/receive channels within;

the values f of these center frequencies_i，{f_i∈[f_min,f_max],i∈{1,…,n}}；

-values of the assigned bandwidths around these center frequencies, { Δ f_i,i∈{1,…,n}}。

Fig. 1a and 1b show the frequency response of an antenna arrangement to be designed at a specified matching level.

FIG. 1a shows an example with three different channels having three center frequencies f₁、f₂、f₃. In this example, having a center frequency f₁And having a center frequency f₃Has a narrow bandwidth and has a center frequency f₂Has a wide bandwidth.

FIG. 1b shows another example with four different channels having four center frequencies f covering approximately the same frequency range₁、f₂、f₃、f₄The four channels each have a fairly narrow bandwidth.

There will typically be multiple solutions that meet the specified requirements so that other constraints can be added.

For example, the specification of an antenna may be defined by the radiation frequencies having a defined bandwidth at a specified matching level and the radiation patterns at these frequencies. The radiation pattern defines the gain that the antenna should achieve in each direction of space, and the corresponding signal-to-noise ratio (SNR) of the radio link using the antenna.

Some constraints may also be defined with respect to the number of elements in the antenna arrangement, with respect to dimensions and/or weight.

Thanks to the invention, the designer of the antenna may be provided with a placement tool that allows to design a placement by assembling predefined elements having predefined resonance modes and whose behavior is known at the time of assembly.

Thus, according to the present invention, a set of rules is defined to efficiently assemble components to match specifications.

Fig. 2 illustrates an antenna arrangement constructed from multiple antenna elements according to some embodiments of the present invention.

The antenna arrangement 200 has a main trunk MT 211 which is connected at a feed 210 of the arrangement. A plurality of secondary trunks { ST }may also be provided_k}. The trunk has a basic pattern defined by its length. The trunk lines may have different form factors, as explained below. In the case shown in the figure, there is only one secondary trunk ST₁212. By definition, all secondary trunks are connected to feeder 210. The main advantage of ST is that its resonance mode can be added to the antenna arrangement without affecting the resonance modes of other antenna elements in the antenna arrangement. It should be noted that the number of STs that can be connected to an MT is limited, depending on the form factor of the main trunk line and the type, number, form factor and connection points of other components carried by said main trunk line MT.

MT or ST can carry multiple branches B_j}. The branches allow the addition of new resonance modes, but the addition modifies some of the resonance modes of the other antenna elements in the antenna arrangement, unless the connection of the added element is at the feed 210 of the antenna. In the exemplary antenna arrangement of fig. 2, there is a first branch B attached to the main trunk 211₁221 and a second branch B attached to a secondary trunk 212₂222. The length of the branches and their form factor also define the resonant frequency of the antenna element. The location of the branch attachment to the trunk is selected by methods discussed further in the description below.

Then, the leaf { L }_iIs added to (master)Main or secondary) main or branch to tune one or more of the center frequencies of the (fundamental or higher order) resonance modes. In the example shown in FIG. 2, there is one leaf L attached directly to the main trunk 211₁231. Two leaves L₃ 233、L₄234 are directly attached to the secondary trunk 212. There are also two leaves L₂232、L₅235 are attached to branches 221, 222, respectively. The geometry, form factor, dimensions and orientation of the leaves define the effect that the leaves will have on the resonant modes of the antenna elements to which they are attached. The position of the leaf defines both the affected (fundamental or higher order) resonance mode and the offset of the resonance frequency brought by the leaf.

Thus, one of ordinary skill in the art of antenna design will be able to use the various elements defined in accordance with the present invention. The present invention also provides the person of ordinary skill with a set of rules to select and place the appropriate elements in the structure of the antenna arrangement to be designed.

Fig. 3a, 3b, 3c, 3d, and 3e illustrate different types of antenna elements according to some embodiments of the present invention and some of its use cases.

The antenna arrangement according to the present invention comprises an antenna element of the type illustrated on one of fig. 3a, 3b, 3c or 3 d.

Fig. 3a schematically shows the main trunk MT. The main trunk is directly connected to the feed line of the antenna arrangement with a connection at that point which is orthogonal or non-orthogonal to the ground plane of the antenna arrangement. The main trunk is a monopole antenna with a length l equal to λ/4, where λ is the wavelength of the fundamental mode of the antenna element, where λ ═ c/f, where f is the radiation frequency in the fundamental mode, and c is the speed of light in vacuum.

The main trunk MT is the basic radiating element of the antenna arrangement. The main trunk line MT is in the frequency range [ f ]_min,f_max]Generating n at a defined frequency_MTA plurality of (primary and higher order) radiation patterns, each of the radiation patterns defining a transmit/receive communication channel. Preferably, the basic mode of MT will be closest to f_minIs related to the frequency of f_minIs the lowest frequency of interest. But some other embodiments are possible.

Fig. 3b schematically shows the secondary trunk line ST. The secondary trunk is directly connected to the feed line of the antenna arrangement with a connection at that point which is not orthogonal to the ground plane of the antenna arrangement. In some embodiments, where MT is not orthogonal to the ground plane, ST itself may be positioned orthogonal to the ground plane. The length l ' of the secondary trunk defines a further resonance frequency f ' of the antenna arrangement, where l '/4 and λ '/c/f '. As explained in more detail below, the secondary mains is in the frequency range f_min,f_max]The inward antenna arrangement adds a number of new resonant frequencies without affecting the resonant frequency defined by the main trunk (provided that the elements maintain a relative position to each other, which does not create electromagnetic interference at that frequency).

The secondary trunk is therefore advantageously used to add a new transmit/receive communication channel to the antenna arrangement.

Fig. 3c schematically shows branch B. The branches add new radiation frequencies and modify some of the radiation patterns of the pre-existing antenna arrangement (the connection point of the branch is not the radiation pattern of the cold spot, if any). Using branches is more complicated than using trunks or leaves, but may provide the advantage of adding some more options to reach the specification of the antenna arrangement, especially if a large number of frequencies are required and the antenna needs to be very compact.

Fig. 3d schematically shows a leaf L. The leaves will typically have a size less than λ^(j)A major dimension of/4, wherein λ^(j)＝c/f(j)，{f^(j)Is the frequency of the fundamental mode and the frequencies of the P higher order modes of the antenna element to which the leaf is attached. The number P is chosen such that f^(P)Equal to the maximum frequency in the list of target frequencies generated by the antenna element in the specification. For example, take the center frequency f of the E5 Galileo navigation signal 1191⁽⁰⁾795MHz as the lower frequency of interest, the second higher frequency of interest is a Wi-Fi channel in the 2.4GHz band with a center frequency of 2472MHz, and the third frequency of interest is the 5GHz band with a center frequency of 5700MHzWi-Fi channels. The E5 frequency can be obtained with a main line of length l of about 6.3cm, which has a fundamental resonance mode at the E5 frequency:the main line being at frequency f⁽¹⁾＝3×f⁽⁰⁾3575,385MHz and f⁽²⁾＝5×f⁽⁰⁾At 5958,975MHz, there are two higher order resonance modes. A first leaf may be added to the main line which will be designed and positioned so that the first higher order resonant mode of the antenna arrangement is shifted down from 3575,385MHz to 2472 MHz. A second leaf may also be added to the main line which would be designed and positioned so that the second higher order resonant mode of the antenna arrangement is shifted down from 5958,975MHz to 5700 MHz. In this example, the maximum length of the leaf is defined by the second higher order resonance mode and is equal to

The leaves are non-resonant elements which are used primarily to control the frequency of the radiation pattern of the main trunk, secondary trunk or branch to which the leaf is attached.

Each of the antenna elements MT, ST, B, and L as defined above is also defined by intrinsic parameters and extrinsic parameters.

The intrinsic parameters include:

its geometry G, i.e. whether it is a one-dimensional (1D), two-dimensional (2D) or three-dimensional (3D) element;

its form factor F, which is to be defined for each geometry;

its dimension D, the number of characteristic dimensions depending on the geometry and form specifications.

Extrinsic parameters include:

its orientation/position O relative to the attached antenna arrangement element; for example, the branches may be positioned perpendicular to the primary or secondary trunk in order to minimize the coupling effect between the two antenna elements; the branches may also be positioned at an angle other than 90 °;

its position P on the element of the attached antenna arrangement; for example, a hot spot (hot spot) is defined at a node (or open location, e.g., open end of MT, ST, or B) of the current on the radiating element; leaves located at hot spots on the primary or secondary trunks have the following effects: all other parameters (O, G, F, D) are constant, shifting the maximum frequency of the fundamental mode or higher order modes of the trunk.

Fig. 3e shows a number of use cases of an antenna element according to the invention. According to the invention, an antenna element of the type depicted in and described in relation to one of fig. 3b, 3c or 3D may be used to generate different types of effects depending on its dimension D. If the specification definition is included in the interval f_min,f_max]A set of values of the resonance frequency of (b), then in the wavelength interval [ lambda ]_min/4,λ_max/4]Define a corresponding dimension interval, wherein_max＝c/f_minAnd λ_min＝c/f_max。

If the dimension D of the antenna element is lower than λ_min/4 (area 1 on fig. 3 e), the antenna element will have the structure and function of a lobe, will not generate any new resonance frequency, and will have a resulting interval f_min,f_max]Depending on the susceptance of the antenna element and its position on the attached MT, ST or B.

If the dimension D of the antenna element is greater than λ_minA/4 and less than lambda_max/4 (area 2 on fig. 3 e), then for some values of the resonance frequency the antenna element will have the function of a branch or secondary trunk, depending on whether the antenna element is located on the feeder of the primary trunk or another location thereon. The antenna element will likely be generated in the interval f_D,f_max]Of one or more new resonance frequencies, where f_DC/4 × D. Depending on whether or not these potential new resonant frequencies are separated from the pre-existing resonant frequencies (at a specified matching level), these potential new resonant frequencies will be the actual new resonant frequencies, or generated in the regionAn amplified bandwidth around the pre-existing resonant frequency within the cell. At the same time, the antenna elements, which are structurally ST or branched, will be in the whole interval f_min,f_max]Which acts as a leaf and shifts some of the pre-existing resonant frequencies within the interval by an amount that depends on the susceptance of the antenna element and its position on the attached MT, ST or B.

Fig. 4a, 4b, 4c, 4d, 4e, 4f, and 4g illustrate examples of differently shaped antenna elements according to some embodiments of the invention.

The figures show some of the possible embodiments of the invention relating to intrinsic parameters of the primary trunk or the secondary trunk.

Fig. 4a, 4b and 4c show embodiments of the invention in which the primary and/or secondary trunks are linear, in 1D, 2D or 3D geometry.

On fig. 4a, a main line with a 1D geometry is shown. The profile F of the main line is rectilinear. The dimension D thereof may be adapted to the frequency required for generating a canonical transmit/receive communication channel of the antenna arrangement.

On fig. 4b, the trunk line is shown with a 2D geometry. The profile F of the main line is sinusoidal. Its dimension D is the full length of the antenna element and is also suitable for generating a canonical transmit/receive communication channel of the antenna arrangement. For the same dimension D, such an element is more compact than the antenna element of fig. 4 a.

On fig. 4c, the trunk lines are shown with a 3D geometry. The profile F of the stem is helical. Its dimension D is the full length of the antenna element and is also suitable for generating a canonical transmit/receive communication channel of the antenna arrangement. For the same dimension D, such an element is more compact than the antenna elements of fig. 4a and 4 b.

On fig. 4D, a trunk line with a geometry close to a 1D geometry is shown. The main line is of a thin strip type, and its profile specification F is linear. The dimension D thereof may be adapted to the frequency required for generating a canonical transmit/receive communication channel of the antenna arrangement.

On fig. 4e, the trunk line is shown with a 2D geometry. The profile F of the trunk approximates a rectangular surface with a conical shape at its base which enables improved control of the matching level of the antenna. The larger dimension D of which is suitable for generating a canonical transmit/receive communication channel of the antenna arrangement. The value of the smaller dimension perpendicular to the larger dimension D is suitable for tuning the bandwidth around the center frequency of the useful resonance mode of the main line: increasing this dimension will increase the bandwidth. This is due to the fact that: the impedance (or admittance) of the antenna element changes more slowly around the center frequency than an antenna (e.g., wire) having a linear form factor.

On fig. 4f, the trunk lines are shown with a 3D geometry. The profile F of the stem is a semi-cylindrical surface with a conical shape at its base. The larger dimension D of which is suitable for generating a canonical transmit/receive communication channel of the antenna arrangement. Such an element has a smaller dimension suitable for tuning the bandwidth around the center frequency of the useful mode of the trunk, but is more compact than the antenna element of fig. 4e for the same dimension D.

On fig. 4g, the trunk lines are shown with a 3D geometry. The profile F of the stem is a cylinder with a conical shape at its bottom. This trunk may define the same frequency and bandwidth as the semi-cylindrical trunk of fig. 4 f. The radiation pattern determined by this cylindrical element will be more uniform and have less spatial diversity than the radiation pattern determined by the semi-cylindrical trunk of figure 4 f.

The antenna elements depicted on fig. 4a, 4b, 4c, 4d, 4e, 4f and 4g are merely exemplary embodiments of antenna elements according to the present invention. Those skilled in the art can derive from these variations of the different form factors without performing inventive activities and without departing from the scope of the invention.

The same geometry and form factor can also be applied to variations of branches or leaves.

Fig. 5a, 5b, 5c, and 5d illustrate examples of different form factor leaf antenna elements according to some embodiments of the present invention.

An example of a 1D leaf with a straight profile specification is depicted on fig. 5 a. In this example, the width of the leaf is 1 mm. The length D is 5 mm. The leaf is positioned perpendicular (O90 °) to the trunk or branch.

According to the invention, the value of the susceptance B (in siemens (s)) seen at the input of the antenna element is calculated for further calculation of the effect of the antenna element on the frequency and bandwidth of the resonant element incorporated in the antenna element.

The calculation is defined using the following criteria:

r is the resistance seen at the input of the antenna element (in Ohm (Ω));

x is the reactance seen at the input of the antenna element (in Ohm (Ω));

z is the impedance seen at the input of the antenna element (in units of Ohm (Ω));

g is the conductance (in siemens (s)) seen at the input of the antenna element;

y is the admittance (in siemens (s)) seen at the input of the antenna element.

Then, the equation for calculating susceptance is as follows:

z ═ R + jX (equation 1)

Y ═ G + jB (equation 2)

The above formula is then solved for the values of the parameters of the antenna elements of fig. 5a to find B, which allows the value of B to be generated.

Alternatively, the following table may be obtained experimentally or by simulation for a range of frequencies f:

f(GHz)	R(Ω)	X(Ω)	G(mS)	B(mS)
					1	2	-1210	0.001	0.826
1.5	1	-870	0.001	1.149
					2	0	-650	0.000	1.538
2.5	1	-493	0.004	2.028
					3	4	-382	0.027	2.618
3.5	11	-316	0.110	3.161
					4	17	-266	0.239	3.744
4.5	14	-228	0.268	4.369
					5	10	-208	0.231	4.797
5.5	12	-197	0.308	5.057
					6	19	-188	0.532	5.265

an example of a 1D leaf with a straight profile specification is depicted on fig. 5 b. In this example, the width of the leaf is 1 mm. The length D was 7.5 mm. The leaf is positioned perpendicular (O90 °) to the trunk or branch.

The following table shows the measurements of the above parameters for various frequencies; alternatively, these parameters may be obtained by direct calculation using equations 1 to 4:

an example of a 2D leaf with a "water drop" form factor is depicted on figure 5 c. In this example, the width and length of the leaf is equal to 5 mm. The leaf is positioned perpendicular (O90 °) to the trunk or branch.

The following table shows the measurements of the above parameters for various frequencies; alternatively, these parameters may be obtained by direct calculation using equations 1 to 4:

f(GHz)	R(Ω)	X(Ω)	G(mS)	B(mS)
					1	2	-638	0.005	1.567
1.5	0	-495	0.000	2.020
					2	1	-409	0.006	2.445
2.5	2	-340	0.017	2.941
					3	15	-275	0.198	3.626
3.5	28	-221	0.564	4.453
					4	35	-171	1.149	5.613
4.5	28	-132	1.538	7.250
					5	21	-107	1.766	8.999
5.5	21	-90	2.459	10.537
					6	25	-77	3.814	11.749

an example of a 2D leaf with a "water drop" form factor is depicted on fig. 5D. In this example, the width and length of the leaf is equal to 7.5 mm. The leaf is positioned perpendicular (O90 °) to the trunk or branch.

The following table shows the measurements of the above parameters for various frequencies; alternatively, these parameters may be obtained by direct calculation using equations 1 to 4:

note that at higher frequencies (5.5/6GHz), D cannot be considered much less than λ/4, since at 6GHz, λ_freespace5cm and λ/4 1.25cm, and D0.75 cm. Thus, the leaves start to have a resonant behavior which may generate a new radiation frequency of the antenna arrangement.

For the same form factor, the table above can be simply calculated for the other dimensions using the equations of equations 1 to 4. These tables may be associated with antenna elements in an antenna element library generated to implement the present invention. Also, an electromagnetic simulation tool may be associated with the library to calculate the input susceptance of the antenna elements in the library in "real-time" for any value of geometry, form factor, dimension, and frequency. Alternatively, a table may be used in combination with an interpolation algorithm to calculate the value of the input susceptance for various form factors and unlisted dimensions and frequencies.

Fig. 5e, 5f, 5g and 5h illustrate examples of different form factor trunk/branch antenna elements according to some embodiments of the present invention.

Fig. 5e shows an ST element or B element with a 1D geometry and straight form factor. The difference with the antenna elements of fig. 5a (i.e. the leaves) is that their main dimension D is defined according to the rule indicated above in relation to fig. 3e, i.e. the main dimension D of the antenna elements is higher than λ_minA/4 and less than lambda_max/4, generated in the interval [ f_D,f_max]And the interval f_min,f_max]With a pre-existing shift in the resonant frequency. Fig. 5f shows the ST element or B element in 2D geometry and curved form factor. The leaf types depicted in fig. 5a to 5d have no equivalent terms.

Fig. 5g shows an ST element or B element with 2D geometry and droplet specifications, similar to the embodiment of fig. 5c and 5D.

Fig. 5h shows an ST element or B element with a 2D geometry and a rectangular form factor with a tapered bottom. The leaf types depicted in fig. 5a to 5d have no equivalent terms.

A 2D profile with a drop or rectangular profile allows for better control of the bandwidth around the target resonant frequency value.

One of ordinary skill in the art will be able to generate tables similar to those described with respect to fig. 5a, 5b, 5c, and 5 d. These tables may be measured values. These tables can be computed using a model. The tables may be calculated using a Smith chart, as further indicated in the description below. These tables may be associated with descriptors of antenna elements stored in a database of antenna elements.

Fig. 6a, 6b, 6c, 6d, 6e, 6f and 6g illustrate examples of assemblies of antenna elements according to some embodiments of the present invention.

The antenna elements of ST type, B type or L type are assembled on the antenna elements of MT type, ST type or B type by direct connection (for example, by soldering).

The following list combinations of antenna elements according to the invention:

-ST on MT;

-B on MT, ST or B;

l on MT, ST or B.

The MT is designated as the main conductive element of the antenna arrangement. ST is the secondary conductive element. When B is directly connected to MT, B may be the secondary conductive element. B may also be a third conductive element when B is connected to ST or another B which is itself directly connected to MT. B may also be a fourth conductive element when B is connected to B or the like which is itself connected to B (which is connected to MT). Similarly, for L, when L is directly connected to MT, L will be designated as the secondary conductive element; when L is connected to B, which is directly connected to MT, L is a third conductive element; or L is the fourth conductive element when L is connected to B which is itself connected to B (which is directly connected to MT). The potted landscape tree can be iteratively expanded by adding new levels of antenna elements (B or L) to better match the specification.

These elements may be stored in a database of discrete simple antenna elements (trunks, branches or leaves). The database may also include an assembly of the discrete antenna elements ST, the ST having B and/or L directly connected thereto; b have other bs attached, each B including or not including L, or any kind of assembly of these discrete elements, no matter how many levels it has in the architecture of the tree bonsai tree defined by the assembly. The susceptance of the elements and assemblies, along with their geometric parameters, may also be stored in a database.

Figure 6a shows a simple configuration of the antenna arrangement in which the secondary trunk line ST is connected at the feed line of the primary trunk line MT. The orientation of the ST with respect to the MT is approximately 45 ° so that the ST is sufficiently far from the MT and the ground plane of the antenna arrangement. The ST is connected at a feed line that is a cold spot (i.e. short circuit, associated with a peak in current) for all the resonant modes of the MT, the resonant modes of the ST do not interfere with the pre-existing resonant modes of the MT, and therefore new transmit/receive communication channels are added to those of the MT.

Fig. 6B shows a configuration of the antenna arrangement in which branch B is attached to the main trunk MT. The dimension of the branch is D, which is determined to generate a value at [ f_min,f_max]New radiation frequencies for antenna arrangements including MT and B in the domain. See the description above with respect to fig. 3 e. The branch is typically located at a cold spot of one of the resonance modes for the MT so as not to modify the frequency of that resonance mode. However, if the junction of the branch is not a cold spot for other modes, the branch will then modify these other resonance modes. There will be a new resonance mode and the resonance mode of the antenna arrangement will be modified before the branch is added.

Then, we will get:

-{f_iMTi ∈ {1, …, n } }: the initial appropriate resonance mode of the MT.

-{f_{j MT+B}J ∈ {1, …, m } }: new appropriate resonance modes for MT plus B.

-{f'_{i MT}I ∈ {1, …, n } }: modified appropriate resonance modes for the MT.

-{f′_{i MT},i∈{1,…,n}}∪{f_{j MT+B}J ∈ {1, …, m } }: including appropriate resonance modes of the antenna arrangement of MT and B.

When the new frequency is sufficiently far from the original frequency, a new transmit/receive communication channel may be defined. Conversely, when one or more of the new frequencies are sufficiently close to the frequencies of the pre-existing resonance modes, the bandwidth around that frequency may be amplified, however, this presupposes that the matching level of the specified values exceeds a predefined threshold.

In other embodiments, branch B may be located on ST in the antenna arrangement as shown in fig. 6c, or branch B' may be located on branch B as shown in fig. 6 d. In both cases, a new resonant frequency is added to the pre-existing resonant frequency before the addition of the new element, thereby creating a new channel or amplifying the bandwidth of the pre-existing channel.

Fig. 6e, 6f and 6g show different embodiments in which a leaf L is added to the primary trunk MT, the secondary trunk ST or the branch B.

When the main dimension D of the leaf L is lower than or equal to lambda^(P)At/4, leaves L will be considered as such, where λ^(P)＝c/f^(P)，f^(P)Is the frequency of the pth higher order mode of the antenna element to which leaf L is attached and is the highest useful frequency generated by the combination of L and MT, ST or B, as explained above.

The intrinsic parameters of the leaf (geometry, form factor, dimensions) will define a first magnitude of the leaf's influence on the frequency of the resonant mode of the antenna element to which the leaf is attached. The effect will vary depending on the frequency of the resonant mode, the magnitude of which is defined by the input susceptance of the leaf. Examples of such effects have been discussed above with respect to fig. 5a to 5 d.

Also, the extrinsic parameters (orientation, position) of a leaf with respect to the antenna element to which it is attached will modify the leaf's effect on the frequency of the resonant mode of that antenna element.

All other things being equal, when a leaf is located at a hot spot of an antenna element (i.e. a node or open circuit of the antenna element's current), the frequency shift imparted by the leaf to the resonant mode of the antenna element to which it is attached will be greatest. Conversely, when the leaf is located at a cold spot of the antenna element (i.e., maximum current or short circuit of the antenna element), the frequency offset will be minimal. Intermediate regions can be easily defined, which can be defined as "warm" spots.

When the main electromagnetic parameters of the antenna element (e.g. input susceptance, input admittance) have been defined as a function of intrinsic parameters (G, F, D) and extrinsic parameters (orientation), the effect on the resonance frequency of the antenna arrangement may be defined by solving equations graphically, analytically or by simulating or modeling equations defining the way of combined admittance/susceptance of the composite antenna element. In contrast, finding the (extrinsic and intrinsic) parameters of the antenna element combinations that will define a compliant antenna arrangement is equivalent to solving the inverse problem. This may also be done graphically, analytically, or through simulation or modeling, as will be further explained in the following description.

Fig. 7a, 7b, 7c, 7d, 7e, and 7f illustrate examples of assemblies of differently shaped antenna elements according to some embodiments of the present invention.

These figures show various examples of assemblies comprising a first antenna element of the MT type and a second antenna element of the ST or B type. However, the second antenna elements can also be of the L type, with the difference being the dimension D of the frequency relative to the highest frequency useful mode of the first antenna element, useful meaning that they allow the targeted frequency to be defined according to the specifications of the antenna.

Fig. 7a and 7B show an antenna arrangement similar to that of fig. 6a and 6B, except that the antenna arrangement of fig. 7a and 7B may also include leaves L as an alternative to the ST-type elements of fig. 6a and the B-type elements of fig. 6B. The first antenna element of the MT type has a 1D geometry.

Fig. 7c and 7D show antenna elements of type B or L, which are 2D elements attached to elements of type MT with 1D geometry.

Fig. 7e shows an ST-type or L-type antenna element, which is a 3D element attached to an MT-type element with 1D geometry.

Fig. 7f shows a B-type or L-type 2D antenna element attached to a MT-type 2D antenna element.

Many other combinations are possible, allowing for the specification of a matched antenna arrangement.

Fig. 8 is a flow diagram illustrating a design method of an antenna arrangement according to some embodiments of the invention.

The specification of the antenna arrangement includes one or more of the following:

list of frequency values { f) at which the antenna arrangement is resonant_iI e {1, …, n } }, so the antenna arrangement is configured to transmit/receive electromagnetic signals;

-bandwidths BW associated with these frequencies at defined matching levels_i，i∈{1，…，n}}；

The antenna arrangement should be adapted to the form factor and geometry.

Some other specification may be added depending at least in part on the antenna arrangement (e.g., the shape of the radiation beam), or primarily on other elements of the T/R processing chain (e.g., power level or SNR). But these specifications are not addressed herein and the invention is applicable to specifications for any kind of antenna arrangement including such requirements.

In order to design an antenna arrangement based on a monopole meeting a specification of a main antenna element, the invention provides, inter alia, a method comprising selecting a main trunk as a first element of the antenna arrangement, the main trunk having a length l and a form factor ff and a geometry g (step 810).

In the first order, the length of the main trunk should be, for exampleWhere λ ═ c/f, f is the resonant frequency of one of the resonant modes of the primary antenna element. In the advantage ofIn an embodiment of (3), f is selected as the lowest frequency value in the list of frequency values and resonance frequencies of the fundamental mode.

The form factor and geometry of the trunk line can be defined as a function of the degree of compaction that must be achieved for a defined target frequency. If the maximum dimension of the antenna element is set to a value that is several times smaller than the length necessary to generate a particular resonance frequency, then it is necessary to use a particular form factor, typically with a 3D geometry (e.g. of the helical type).

At step 820, the electrical response of the antenna arrangement is modeled to determine a value of the frequency of the resonant mode. Step 820 is implemented after the first step 810 described above for a single antenna element (i.e., main trunk, N set to 1), or as part of an iterative step (N ═ N +1) to be performed until all target frequencies and bandwidths of the specification are obtained (step 845). There, a number of antenna elements (secondary trunks, branches and/or leaves) have been picked up from a bank of antenna elements and added to the antenna arrangement. The values of all frequencies associated with the resonance modes of the antenna arrangement may be determined by analytical calculations using an electrical model of the antenna arrangement. The model can be used for simple structures and is not generally used for complex structures. Instead of an analytical model, a graphical representation (e.g., a Smith chart) may be used to determine the values of the frequencies of the resonance modes. Electromagnetic simulation tools can be used to find suitable solutions more quickly. Examples of analytical models, graphical representations, and simulation tools are further discussed in the following description of various embodiments of the invention.

At step 830, the values of the resonant frequency, the matching level and the bandwidth of the antenna arrangement are compared to the specification.

Steps 820 and 830 may be repeated multiple times if simple adjustment of parameters of the same structure of the antenna element allows convergence to a normative value.

If all values of the specification (frequency, matching level, bandwidth) are tested (step 840) and confirmed to be satisfied, the process ends (step 845). Otherwise, the electrical states of the antenna elements currently in the antenna arrangement to which new antenna element points may be added are mapped (step 850). It is worth noting that hot and cold spots should be marked for each resonance mode. At the point of the first category, a leaf may be added that will bring the maximum shift in the frequency of the resonant mode of the antenna arrangement (all other conditions being the same). At a point of the second category, a secondary trunk or branch may be added which, if the specification is not fully met, will bring about a minimum shift in the resonant frequency of the resonant mode of the antenna arrangement and add a number of new resonant frequencies to the antenna arrangement.

Then, at step 860, a new antenna element is selected in the antenna element library to be added to the antenna arrangement at the relevant point of the relevant pre-existing antenna element. Guidance for selecting a type of antenna element based on the type of adjustment to be made to a target specification of an antenna arrangement is further provided in the description below. Before adding an antenna element to an appropriate position of an antenna arrangement, the antenna element should be configured, i.e. its adjustable parameters (dimension(s), form factor, etc.) should be defined, to obtain sufficient susceptance that will result in the required effect on the frequency values and bandwidth that have to be adjusted.

The loop is then iterated until the specification is fully met.

Fig. 9 is another flow diagram illustrating a design method of an antenna arrangement according to some embodiments of the invention.

In such embodiments of the invention, the specification may be restated as:

{f_i，i∈{1，...，n}}；f_i∈[f_min，f_max]

{Δf_i，i∈{1，...，n}}；

all specifications can be satisfied with a single trunk. At step 910, the definition may be used to generate the specifications listed in the specificationNumber n of resonance modes of the main line of frequencies_MT. At step 920, the specification is tested for satisfaction with respect to the number of frequency values (or channels). If the number is correct (step 930), the frequency value itself must be tested (step 940). If all frequency values match the specification, the bandwidth must be tested (steps 99G and 99H). If the bandwidth passes the test, it is declared that the specification is met (step 99I). Otherwise, a new resonance mode must be added to control the bandwidth by adding secondary main lines (ST) and/or branches (B); the resonant frequency value may be controlled by adding leaves (L) on the secondary main line (ST) or branch (B) (step 99E). The results are then tested (step 99F). In case a new antenna element is needed, the new antenna element is added by an iterative loop (step 99E/step 99F).

Returning to step 940, if some of the frequency values are different than the specified frequency values, the frequency values corresponding to each resonant mode of the primary trunk line may be shifted by a predetermined amount (step 950). The amount of offset will depend on the parameters of the leaf (its geometry (1D, 2D, 3D), its form factor, its characteristic dimensions) and the position and orientation of the leaf on the trunk. The frequency values are then tested against the specifications in the new configuration (step 955). If the frequency value passes the test, the method continues with testing the bandwidth (steps 960 and 99D). If the bandwidth passes the test, it is declared that the specification is met (step 99I). If the bandwidth does not pass the test, the method branches to step 99E. At the output of test 955, if one of the frequency values fails the test, a new channel is generated, tested, and then the resonant frequency value and bandwidth are tested (step 970, step 975, step 980).

Returning to step 920, if the number of frequencies generated on the primary trunk is below the number required by the specification, the missing channel may be generated by adding a Secondary Trunk (ST) and/or a branch (B) (step 99A). The number of channels is then tested using a loop with step 99A (step 99B). A list of resonant frequencies is then built (step 99C) and the method branches to step 940.

As explained above, the intrinsic parameters of the antenna elements (MT, ST, B, L) that can be tuned to meet the specifications are their geometry (1D, 2D, 3D), their form factor and their characteristic dimensions. Furthermore, the influence of the antenna element on the resonance frequency of the overall antenna arrangement will depend on the composition of the antenna element (the individual elements or the elements connecting the sub-elements (branches or leaves)) and the location of the antenna element with respect to the hot and cold spots of the attached MT, ST or B.

The calculation of the resonance frequency and the corresponding bandwidth for the resulting exact matching level of the antenna arrangement, the parameter set of each of the antenna elements and their position may be performed analytically, graphically or by simulation. Likewise, a solution to the inverse problem (finding the set of antenna elements, the intrinsic parameters of the antenna elements and the position of the antenna elements generating the set of resonance frequencies with a defined bandwidth for the matching level) can also be obtained by one of these methods. Also, some artificial intelligence or knowledge-based tools (e.g., neural networks) may be used with the tools to simulate or model solutions according to parameters to more quickly explore the solution space of the inverse problem. Simulation tools known to those skilled in the art of antenna design are for example CST^TM、HFSS^TM、Feko^TMOr Comsol^TM. Any other proprietary software with similar functionality may be used.

According to the invention, for designers who have to design the antenna arrangement according to specifications, different types of antenna elements (primary trunk, secondary trunk, branches, leaves) have the following uses and can be combined to meet the parameters of the specifications (resonance frequency and bandwidth for a defined matching level):

-the main trunk line is used to generate a set of resonance frequencies corresponding to the appropriate resonance modes of the main trunk line;

-a secondary trunk of the feeder connected to the primary trunk for generating a new set of resonant frequencies corresponding to the appropriate resonant mode of the secondary trunk;

-a branch connected to the Main Trunk (MT), the Secondary Trunk (ST) or another branch (B) for generating a new resonance frequency of the antenna arrangement comprising MT, ST and pre-existing B; these resonance frequencies can be separated from the resonance frequencies of the appropriate modes of MT, ST and pre-existing B, or generate bandwidths at defined matching levels around the pre-existing appropriate modes, or a combination of both;

a leaf, the main dimension D of which is defined according to the rules explained above with respect to fig. 3e, and which is connected to the Main Trunk (MT), the Secondary Trunk (ST) or the branch (B) for shifting the frequency of the appropriate mode of the antenna assembly connected thereto.

Based on these design rules and using the iterative algorithms, calculations and tools described in the specification, a database can be built that allows matching antenna elements of various specifications.

Fig. 10a, 10c, 10e and 10g show examples of assemblies of antenna elements according to some embodiments of the present invention, and fig. 10b, 10d, 10f and 10h show frequency responses of the responses of these assemblies.

In fig. 10a, the antenna arrangement 1000a is a simple monopole antenna with an omnidirectional radiation pattern in the azimuth plane. The dimensions of the arrangement are chosen such that the antenna is suitable for operation in the ISM (industrial, scientific, medical) band, the VHF band or the UHF band. It can be considered as a tree that includes only trunk 1010. The tree is on the ground plane 1030.

The main trunk 1010 is formed of a conductive material, a metal wire or a metal strip, which is spread out over a physical length l, which is defined according to the desired radiation frequency of the fundamental mode as already explained above. At this frequency, l ═ λ/4. The trunk may be inscribed in a plane. In some embodiments, for example when the antenna arrangement is manufactured using microstrip technology, the plane in which the trunk is inscribed may be parallel to the ground plane, or in solutions where the antenna and ground plane are designed to be co-planar, the trunk may be inscribed in the ground plane. In such an arrangement, the antenna may be inscribed on the surface of the substrate, and the ground plane may be inscribed on the floor of the substrate. In other embodiments, the plane into which the trunk lines are inscribed is perpendicular to the ground plane. The trunk lines may alternatively be inscribed in a non-planar surface or volume structure. Such a form factor is advantageous for increasing the compactness of the antenna arrangement for a given physical length l.

The ground plane 1030 is the metal chassis of the PCB structure, which includes the excitation circuitry that feeds the RF signal to the trunk at its mechanical and electrical connection points 1040.

At this step, it is useful to introduce the concept of "electrical length" of the radiating element. Electrical length l of element with physical length l at wavelength λ_e(λ)Is prepared from_e(λ)L/λ. Then, if the radiation has an electromagnetic dielectric constant of ε_rIn a medium of (1), whereinWill obtain In the air, wherein ∈_r1, will yield l_e(λ)＝l×f/c。

The electrical length may be expressed in degrees or radians. For example, for l_e(λ)1/4 (in λ), this value can be expressed as l_e(°)90 (in degrees) or l_e(rad)Pi/2 (in radians).

The different radiation modes are essentially defined by the electrical length of the radiation pole element:

the fundamental mode consists of the electrical length l of the radiating element equal to 1/4(λ) (first harmonic)_e(λ)Definition, where λ ═ c/f, f is the radiation frequency at the fundamental mode;

the first higher order mode consists of 3/4(λ)₁) Electrical length of (third harmonic) radiating elementDefinition of where₁＝c/f₁，f₁Is the resonant frequency of the first higher order mode of the radiating element;

the second higher order mode is defined by the electrical length of the radiating element equal to 5/4(λ 2) (fifth harmonic)Definitions, where λ 2 ═ c/f₂，f₂Is the resonant frequency of the second higher order mode of the radiating element;

the third higher order mode consists of 7/4(λ)₃) (seventh harmonic) electrical length of radiating elementDefinition of where₃＝c/f₃，f₃Is the resonant frequency of the second higher order mode of the radiating element.

The resonance frequency f of the fundamental mode and the resonance frequency f of the first higher-order mode₁And the resonant frequency f of the second higher order mode₂Denoted by reference numerals 1010b, 1011b, 1012b, respectively, in the graphical representation of the frequency response of the radiating element (fig. 10 b).

The antenna arrangement 1000c of fig. 10c includes a leaf (L)1020 located at a point 1025 on the main trunk 1010. The leaves are also metallic and are mechanically and electrically connected to the main rail, their position 1025 being typically selected to maximise their effect on the shift in frequency of one of the resonant modes of the main rail. The shift in frequency will also depend on the geometry, form factor, dimensions, and orientation of the leaf 1020.

These dependencies are disclosed in european patent application publication number EP2016/306059.3, the antenna arrangement resembling a compact tree structure that resembles the structure of a bonsai in some respects.

It is also possible to define an equivalent electrical length l_e(λ)eq. For example, if a leaf with a defined geometry, form factor and dimensions is added to a defined location on a main trunk with a defined orientation, the combination of the trunk and leaf will have a general formula of l_e(λ)eq＝l×f/c+Δl_e(λ)(f) Defined equivalent electrical length, where Δ l_e(λ)(f) Is a function of the frequency f, which is a variation of the electrical length of the mains as a result of adding leaves.

There may be multiple leaves. A leaf may be viewed as a structure that extends the length of the antenna in a defined direction by a defined amount. The leaves may or may not be inscribed together in the same plane or in different surfaces. The leaves may or may not be coplanar with the trunk.

FIG. 10d shows the shift in resonant frequency of the main trunk 1010 by the leaf 1020:

f becomes f' (marker 1010d on FIG. 10 d);

-f₁becomes f₁' (marker 1011d on FIG. 10 d);

and f₂Becomes f₂' (item 1012d on FIG. 10 d).

It can be seen that for the first higher order mode, the shift in frequency is greatest: the difference between locations 1011b and 1011d is greater than the difference between locations 1010b and 1010d and the difference between locations 1012b and 1012 d. This is determined by the position of the leaf on the main trunk. It can also be seen that the resonance frequency is shifted to a lower value due to the increased total electrical length of the antenna arrangement.

The antenna arrangement 1000e of fig. 10e includes a Secondary Trunk (ST)1050, which ST 1050 is located at the point 1040 of mechanical and electrical connection (also referred to as the feeder point) of the primary trunk 1010. The ST is also metallic and is mechanically and electrically connected to the main rail.

As already discussed, ST 1050 may have different geometries, form factors, dimensions, and orientations.

Since ST 1050 is connected to the only point that is the cold spot for all resonance modes of main rail 1010, there is no effect on the frequencies of these resonance modes, which remain unchanged, as shown in FIG. 10f, where f, f₁And f₂In fig. 10b at the same positions 1010b, 1011b and 1012 b.

If required by the specifications, the following new radiation frequencies are created by adding ST 1050:

-f⁽¹⁾1021 f;

-f₁ ⁽¹⁾and 1022 f.

The antenna arrangement 1000g of fig. 10g includes a branch (B)1060, which B1060 is located at a point 1065 of the main trunk 1010. The branches are also metallic and are mechanically and electrically connected to the main trunk, their location 1065 being generally selected to minimize their effect on the radiation frequency of the resonant mode of the main trunk. Cold spots for one or more of the radiation patterns of the main trunk are preferred.

As shown in fig. 10h, at frequency f⁽²⁾A new radiation pattern (labeled 1011h) is created, while the frequency f of the first order resonance pattern₁(labeled 1011b) is unaffected because point 1065 is a cold spot for this first order resonance mode. The frequency of the fundamental resonance mode (f, 1010b) and the frequency of the second higher order mode (f₂1012b) are shifted to lower frequencies (f', 1010h, and f)₂"，1012h)。

Fig. 11a, 11c and 11e show the distribution of current and voltage of the fundamental, first and second higher order modes of the monopole antenna, and fig. 11b, 11d and 11f show the calculation of the input admittance of the antenna arrangement at each of these modes on the Smith chart, respectively.

Fig. 11a shows the distribution of current (curve 1110a) or the distribution of voltage (curve 1120a) for the fundamental mode (or first harmonic) of a monopole antenna of length/between the connection to the feed line 1140 (or short circuit point) and the open circuit point 1130, which is the tip of the monopole antenna. Resonance frequency f of fundamental mode₀ ⁽⁰⁾Is defined as:

electrical length of antenna at fundamental modeRepresented by curve 1110b on fig. 11b, curve 1110b shows a Simith circular plot characterizing the antenna at the fundamental mode. Curve 1110b covers a half turn clockwise on the Smith chart.

The normalized input admittance of the antenna is defined as:wherein, Y_CIs the characteristic admittance of a monopole antenna.

At the time of the basic mode, it is,is infinite at SC point and is therefore given by the following equation:

likewise, fig. 11c shows the distribution of the current (curve 1110c) or the distribution of the voltage (curve 1120c) for the first higher order mode (or third harmonic) of a monopole antenna of length/between the connection to the feed line 1140 (or the short circuit point) and the open circuit point 1130, which is the free end of the monopole antenna. Resonant frequency f of the first higher order mode₁ ⁽⁰⁾Is defined as:

can also obtain f₁ ⁽⁰⁾＝3f₀ ⁽⁰⁾。

Electrical length of antenna at first higher order modeRepresented by curve 1110d on fig. 11d, curve 1110d shows a Smith chart characterizing the antenna at the first higher order mode. The curve 1110d covers one and a half turns clockwise on the Smith chart.

Normalized input admittance of an antenna at a first higher order modeIs infinite at SC point, and thus consists ofIt is given.

Likewise, FIG. 11e shows the connection to the feed line 1140 (or short circuit point) and the open point 1130, which is the free end of the monopole antenna, the distribution of the current (curve 1110e) or the distribution of the voltage (curve 1120e) for the second higher order mode (or fifth harmonic) of the monopole antenna of length/. Resonant frequency f of the first higher order mode₂ ⁽⁰⁾Is defined as

Can also obtain f₂ ⁽⁰⁾＝5f₀ ⁽⁰⁾。

Electrical length of antenna at second higher order modeRepresented by curve 1110f on fig. 11f, curve 1110f shows a Smith chart characterizing the antenna at the second higher order mode. Curve 1110f covers two and a half turns clockwise on the Smith chart.

Normalized input admittance of an antenna at a second higher order modeIs infinite at SC point and is therefore given by the following equation:

the representations and calculations of fig. 11a to 11f can of course be generalized for higher order modes.

Using the Smith chart allows combining the admittance/susceptance of the various antenna elements at their connection points, as explained below.

Fig. 12a, 12b and 12c show the calculation of the equivalent physical length of a leaf, and fig. 12d, 12e and 12f show the effect of a leaf located on a trunk on the fundamental mode, the first higher order mode and the second higher order mode of the trunk, respectively.

Figure 12a shows an antenna arrangement 1200, the antenna arrangement 1200 having a leaf 1220 connected to a main trunk 1210 at point P, the leafTwo fragments are defined: has a length ofFragment 1211 and length ofA segment 1212 of such that

Fig. 12b shows the calculation of the equivalent physical length and admittance of the leaf 1220.

Defining the equivalent physical length of a leaf at frequency f as having the same input admittance Y as the leaf_IN(f) Length l of the linear antenna element_eq.Leaf(f) (wherein l_eq.Leaf(f)∈[0,λ/4]). Then one must solve: y is_IN(f)＝Y_Leaf(f)。

Y_Leaf(f) Is a function of the intrinsic and extrinsic parameters (geometry, form factor, dimensions, and orientation) of the leaf 1220.

If the equivalent linear antenna element has an input admittance Y at the connection P12201 to the main trunk 1210_IN(f) And has an admittance Y at its distal end OC 12202_LThen the following relationship between the admittances defined on the leaf can be obtained:

when the propagation medium is ambient air, there may be β -2 pi/λ or β -2 pi × f/c. Equation 5 can then be solved graphically or analytically.

The pattern resolution is shown on the Smith chart of figure 12 c.

If it will be_e(λ)eq.Leaf(f) Defined as the equivalent electrical length (l) of the leaf 1220_e(λ)eq.Le_af(f)＝l_eq.Leaf(f) Lambda,/wherein_e(λ)eq.Leaf(f)∈[0,1/4]) Then, starting at OC position 1210c and representing the equivalent electrical length l_e(λ)eq.Leaf(f) After clockwise rotation of arc distance 1220c, the normalized input admittance of the leaf may be read at point 1230c on the Smith chart(which is equal to)。

The analytical solution of equation 5 takes advantage of the fact Y_L＝Y_OC0. Thus:

assuming leaves 1220 are lossless, then Y can be assumed_Leaf(f)＝j×B_Leaf(f) In that respect Thus, there may be:

wherein

It is converted into:

wherein

Equations 7 and 8 define the relationship between the susceptance at the feed point 12201 of the leaf 1220 and the equivalent length of the leaf at frequency f.

In an embodiment, FIG. 12d shows the effect of adding leaf 1220 on the frequency of the fundamental mode of primary trunk 1210.

In this embodiment, by way of example only:

and therefore the number of the first and second channels,i.e. the length of the main trunk is equal to the resonance frequency f corresponding to the fundamental mode₀ ⁽⁰⁾One quarter of the wavelength of (a).

The parameters (geometry, form factor, dimensions) of the leaf 1220 are such thatThe leaf 1220 is particularly of sufficiently small dimensions that its equivalent length is lower than

On the Smith chart of FIG. 12d, starting from the OC point 1210d on the left hand side of the chart, which defines the circle origin of the admittance, then by adding the equivalent electrical length ofThe antenna segment of (a) is moved clockwise starting with a segment at the far end of OC.

At frequency f₀ ⁽⁰⁾Has an electrical length ofGenerating a normalized input admittanceSo that

At the frequency f of the fundamental mode of the antenna arrangement₀ ⁽⁰⁾Normalized admittance at point P12201Normalized input admittance for fragment 1211 (fragment 1220d)Normalized input admittance to leaf 1220 (segment 1230d)The sum of (a) and (b).

Then, the total normalized input admittance at point P is obtainedNamely:

thus, the leaves are at f₀ ⁽⁰⁾With an added rotation of 0.046.

Then, the electrical length of the main trunk 1210 is added asThe second segment 1212, the second segment 1212 defining a rotation 1240d, the rotation leading to a point 1250d on the Smith chart, the point 1250d defining a normalized input admittance at which the antenna arrangement may be readTotal rotation Rot of_Ant。

Wherein Rot_{Leaf 1220}0.046 (arc 1230 d).

In the example shown in FIG. 12d, there may be

Therefore, there may be equivalentsHas a length ofAntenna element 1200 with an equivalent length higher than f₀ ⁽⁰⁾At a quarter wavelength. Thus, at frequency f₀ ⁽¹⁾A new basic pattern of the antenna arrangement of (a) is such thatThe leaves 1220 thus reduce the frequency of the fundamental mode of the antenna arrangement 1200.

Figure 12e shows the effect of adding leaf 1220 on the frequency of the first higher order mode of main trunk 1210 in an embodiment.

Can haveAnd therefore the number of the first and second channels,

the parameters (geometry, form factor, dimensions) of the leaf 1220 are such thatThe leaf 1220 is particularly of sufficiently small dimensions that its equivalent length is lower than

On the Smith chart of fig. 12e, starting from the OC point on the left hand side of the chart, which defines the origin of the circle of admittance, then moves clockwise from a segment with OC at the far end by adding antenna segments of equivalent electrical length.

At frequency f₁ ⁽⁰⁾Has an electrical length ofGenerating the regression of the first fragment 1211 ofNormalized input admittanceSo that

Frequency f at the first higher order mode of the antenna arrangement₁ ⁽⁰⁾Normalized admittance at point P12201Normalized input admittance for fragment 1211Normalized input admittance with leaf 1220The sum of (a) and (b).

From normalized input admittance ofStarting at point P, then adding main trunk 1210 electrical length ofAnd then determines the normalized input admittance of the combined antenna arrangement 1200.

Equation 10 applies to₁ ⁽⁰⁾Substitution of f₀ ⁽⁰⁾. Thus obtaining

Thus, may have an equivalent length ofAntenna element 1200 with an equivalent length higher than f₁ ⁽⁰⁾Three-quarters of a wavelength. Thus, at frequency f₁ ⁽¹⁾Antenna arrangement ofIs such thatThe leaves 1220 thus reduce the frequency of the first higher order mode of the antenna arrangement 1200.

Figure 12f shows the effect of adding leaf 1220 on the frequency of the second higher order mode of main trunk 1210 in an embodiment.

Can haveAnd therefore the number of the first and second channels,

the parameters (geometry, form factor, dimensions) of the leaf 1220 are such that Y is_LeafN(f₂ ⁽⁰⁾) J × 3.0. The leaf 1220 is particularly of sufficiently small dimensions that its equivalent length is lower than

On the Smith chart of fig. 12f, starting from the OC point on the left hand side of the chart, which defines the origin of the circle of admittance, then moves clockwise from a segment with OC at the far end by adding antenna segments of equivalent electrical length.

At frequency f₂ ⁽⁰⁾Has an electrical length ofGenerating a normalized characteristic admittance of the first segment 1211 ofSo that

Second higher order mode in an antenna arrangementFrequency f of₂ ⁽⁰⁾Normalized admittance at point P12201Normalized input admittance for fragment 1211Normalized input admittance with leaf 1220The sum of (a) and (b).

From normalized input admittance ofStarting at point P, then adding main trunk 1210 electrical length ofAnd then determines the normalized input admittance of the combined antenna arrangement 1200.

Equation 10 applies to₂ ⁽⁰⁾Substitution of f₀ ⁽⁰⁾. Then obtain

Thus, may have an equivalent length ofAntenna element 1200 with an equivalent length higher than f₂ ⁽⁰⁾At five quarter wavelengths. Thus, at frequency f₂ ⁽¹⁾A new basic pattern of the antenna arrangement of (a) is such thatThe leaves 1220 thus reduce the frequency of the second higher order mode of the antenna arrangement 1200.

In these embodiments, where the primary dimension of the leaf 1220 added to the main trunk 1210 is small relative to a quarter of the wavelength of the radiation mode of the main trunk, the leaf 1220 lengthens the main trunk, which in turn advantageously results in a reduction in the value of the resonant frequency of the appropriate mode of the antenna arrangement.

When a leaf is located at a point P equivalent to an open circuit (or hot spot) for a given mode, the leaf is fully active for that mode (i.e., the largest additional rotation is generated on the Smith chart), thus bringing a shift in the resonant frequency that is the largest for that mode.

In contrast, when a leaf is located at a point P equivalent to the short circuit (or cold spot) of the mode, the leaf is "transparent" (i.e., no additional rotation is generated on the Smith chart) and therefore does not introduce a shift in the resonant frequency for that mode.

When a leaf is located at a point P between the hot and cold spots, the frequency offset introduced by the leaf increases as the leaf moves closer to the hot spot, and decreases as the leaf moves closer to the cold spot.

For a given mode, the position of the point P connecting the leaves defines its electrical state parameter, which is a key parameter for controlling the magnitude of the frequency offset brought by the leaves.

The top end of main trunk 1210 is the hot spot for all modes, while its bottom end is the cold spot for all modes.

In some examples, the calculation of the resonant frequency with knowledge of the design parameters of the antenna arrangement (solution to the direct problem) and the calculation of the design parameters to obtain a defined set of resonant frequencies (solution to the inverse problem) may also be performed analytically using the relationships presented below.

The above definitions may be used. Also, the resonance frequency f is given. Some characteristics of the main trunk 1210 are fixed: the geometry is 1D and the form factor is a straight line. The dimensions (length) of the monopole antenna may vary. The leaf 1220 is 2D. The leaf profile and dimensions may vary and allow its equivalent length at frequency f to be calculated(wherein) And its input susceptance B at frequency f_Leaf(f) (wherein B_Leaf(f)∈[0,+∞[)。

Starting from the standard equation for the composition of the input admittance from segment 1211 and leaf 1220, seen at point P of the position of leaf 1220 on main trunk 1210, and from the relationship between susceptance and admittance (susceptance being the imaginary part of admittance), can be written as:

compounding the admittance seen in P with the segment 1212 can be written as:

the antenna arrangement 1200 will be at frequency f_resIs resonant such that the input admittance at the feed point of the antenna has an infinite imaginary part (or susceptance) or its inverse is null. Starting from equation 12, leaf 1220 is found for the resonant frequency f_resExpression of input susceptance at point P:

it is worth noting thatWhen k is equal to N, the termIs empty at the hot spot and the input susceptance of the leaf has the greatest effect at this point P. In contrast, at cold spots, B_LeafP(f_res) The effect of (c) is minimal. Thus, an efficiency factor (or phase) of the position of a leaf on a main trunk may be definedConversely, defining a transparency coefficient), the efficiency factor is a function of the leaf's effect on the combined input susceptance at point P, as defined by equation 11.

To solve the direct problem, all design parameters are first set, and the resonant frequency of the antenna arrangement 1200 is the frequency f that solves equation 13_i。

For all frequencies f_iI ∈ {1,2,. n }, the solution to the inverse problem starts with a list of frequencies defined by the specification of the antenna. The designer or design tool provided in accordance with the present invention will adjust the design parameters of the antenna to define a plurality of resonant modes, all frequencies of which satisfy equation 13.

In this embodiment with straight main trunks and a single leaf, the design parameters that the designer can adjust to meet the specification in terms of frequency are:

length l of main trunk 1210;

position of leaf 1220 on the main trunk line

The geometry, form and dimensions of the leaf 1220 and its orientation with respect to the main trunk, these parameters defining the input susceptance function B at the point P_Leaf(f)。

According to the present invention, the input susceptance function at a point P on an antenna element of a 1D linear monopole antenna (whether the antenna element is a main trunk, a secondary trunk, or a branch) as a leaf connection can be derived from equation 13.

Therefore, when leaf B is known_Leaf(f) The direct problem can be solved when inputting the susceptance function and its position P, i.e. the resonance frequency of the antenna arrangement can be determined. The inverse problem may have multiple solutions (i.e., find pairs (P, leaves) that allow the generation of a normal resonance frequency). The plurality of leaves as a solution to the inverse problem have susceptances that satisfy equation 13 when located at point P. The leaf may be selected in a database of antenna elements. The susceptance function may be expressed as a function of the leaf's design parameters, geometry G,A form factor F, a characteristic dimension D, and an orientation O relative to the antenna element to which it is connected. Thus, there may be:

B_Leaf(f)＝B(f,G_Leaf,F_Leaf,D_Leaf,O_Leaf) (equation 14)

According to the invention, information about the susceptance function can be obtained and used according to different embodiments:

for G_Leaf,F_Leaf,D_Leaf,O_LeafThe value of the susceptance function at each frequency can be measured experimentally; these values are then stored in a look-up table (LUT) or database with descriptors of the corresponding leaves; outliers in the measurements can be cleared; these values can also be statistically normalized using methods known to those of ordinary skill;

the value of the susceptance function can also be calculated using electromagnetic simulations or models; the algorithm that performs the calculation may then itself be stored in a program developed to calculate the resonant frequency of the antenna arrangement (direct problem) or its design parameters (inverse problem), or the simulation results may themselves be stored in a database or look-up table, as in the previous embodiment;

in some embodiments, in the case where the geometry G, the form factor F and the orientation O of the leaf are simple, B can be calculated in a simple manner_Leaf(f) As illustrated above with respect to fig. 5a and 5 b; for example, when a leaf is a straight line element positioned perpendicular to the straight 1D main trunk (fig. 5a and 5b), equation 14 becomes:

in some embodiments of the invention, the above different methods may be combined. For example, experimental measurements may be used for some parts of the specification field (geometry, form factor, dimensions, orientation), while simulations or models may be used for other parts of the specification field. Furthermore, experimental measurements may be used to calibrate the simulation or model. Simulations or models may also be used to interpolate or extrapolate the values of the susceptance function between or beyond values that have been obtained experimentally.

The artificial intelligence algorithm may also be applied to the database/look-up table/simulation/model defined above to solve the inverse problem, i.e. to find one or more sets of design parameters that meet the specifications for an antenna arrangement comprising a plurality of frequencies. For example, various neural networks may be used to explore the solution space much more quickly than pure brute force exploration.

FIG. 13a shows two leaves located on a trunk; fig. 13b and 13c, 13d and 13e, and 13f and 13g respectively show the configuration of the antenna arrangement of fig. 13a and the calculation of its input admittance using the Smith chart.

Fig. 13a shows an antenna arrangement 1300 having a first blade 132, the first blade 132 being connected to a primary trunk 1310 at a point P, the point P defining a length ofA top segment 1311 and a bottom segment, which itself is divided into two segments by a point Q, of lengthSegment 1312 and a length ofAnd a second leaf 1322 at point Q. The length of the segment is satisfied

FIGS. 13b and 13c show the starting point of an iterative design process in which only the length isThe frequency f for the monopole in the fundamental mode is reproduced on the Smith chart (see fig. 13b)₀ ⁽⁰⁾Equivalent electrical length of(see FIG. 13 c). The Smith chart also allowsComputing normalized input admittance of an antenna arrangement

Fig. 13d and 13e illustrate the effect of adding the first leaf 1321 on the frequency of the fundamental mode of primary rail 1310 in an embodiment.

In this embodiment, the length of the segments 1311, 1312, 1313 (see fig. 13d) may be defined as a fraction of the wavelength of the fundamental mode.

The definition of parameters (geometry, form factor, dimensions) of the leaf 1320 allows the input admittance Y of the leaf to be calculated_Leaf(f₀ ⁽⁰⁾). The leaves 1321 are in particular of sufficiently small dimensions that their equivalent length is lower thanAnd:

on the Smith chart of fig. 13e, starting from the OC point on the left hand side of the chart, which defines the origin of the circle of admittance, then moves clockwise from a segment with OC at the far end by adding antenna segments of equivalent electrical length.

The procedure and results performed are similar to the procedure shown in fig. 12d explained in the above description.

Fig. 13f and 13g illustrate the effect of adding second leaves 1322 on the frequency of the fundamental mode of primary mainline 1310 in an embodiment.

Equation 10 may be generalized and the effect of second leaf 1322 and third segment 1313 on the composite admittance added.

In determining the total rotation Rot_AntCan read the normalized input admittance of the antenna arrangement

Rot_AntThe following equation 15 is satisfied:

rot is calculated as exemplified above with respect to equation 10_Leaf1321And Rot_Leaf1322。

The increase in the equivalent electrical length of the antenna with two leaves is higher than with only one leaf. Therefore, the frequency reduction of the fundamental mode is higher. For the fundamental mode, the new resonance frequency f₀ ⁽²⁾Will be such thatThe following inequalities are possible: f. of₀ ⁽²⁾<f₀ ⁽¹⁾<f₀ ⁽⁰⁾。

The same procedure and conclusions hold for the higher order modes.

The direct problem of defining frequency groups of resonance modes of an antenna arrangement of the type of fig. 13a can also be solved analytically using the same rules of the above explained combination of admittance/susceptance of the antenna elements at their connection points.

For this reason, the equivalent length defined in such a manner as to satisfy the following equation 16 isInstead of fragment 1311 (which is electrically connected in parallel with leaf 1321 at point P):

when adding the second leaf 1322 at point Q, equation 13 is used by the following alternative:

by usingReplacement of

By usingReplacement of

Replacement of leaves with leaves Q.

Then, the solution to the problem must satisfy equation 16 above and equation 17 below:

the solution to the inverse problem starts with a list of frequencies defined by the specification of the antenna, f_iI ∈ {1,2,. n }. The designer will adjust the design parameters of the antenna to define a plurality of resonance modes whose frequencies satisfy equations 16 and 17.

In this embodiment with a straight main trunk and two leaves, the design parameters that the designer can adjust to meet the specification in terms of frequency are:

length of main trunk 1310

Position P of leaves 1321 and 1322 on the main trunk and

the geometry, form and dimensions of the leaves 1321, 1322 and their orientation with respect to the main trunk, these parameters defining the input susceptance function B at the points P and Q_Leaf(f)。

Made above in connection with B_Leaf(f) The same applies to this embodiment.

In this embodiment with a main trunk and two leaves, 11 independent design parameters can thus be defined, fourLength parameterThree of (1), consisting ofFour length parameters of the link and four parameters of each leaf (geometry, form factor, dimensions and orientation):

-G_P,Q∈{1D,2D,3D}

-F_P,Q∈{wire,triangle,drop...}；

-

-O_P,Q∈[90°-α,90°+α]。

the "wire" geometry/form factor is shown in fig. 5a and 5b, which have been described above. The "drop" geometry/form factor is shown in fig. 5c and 5 d. The "triangle" geometry is a triangular 2D leaf.

The characteristic dimension D must be lower thanAs already indicated.

The orientation may be defined by the angle between the characteristic axis of the leaf and the main trunk.

As discussed above, the solution to the inverse problem is to find a set of design parameters that satisfy equations 16 and 17 above for all frequencies of the specification. There may not be an accurate solution for all frequencies. The cost function may then be defined as the sum of the squares of the differences between each actual susceptance and each target susceptance for each frequency of the specification. The square of the difference may be weighted to contribute to one or more of the frequencies in the specification. The cost function can then be expressed as:

of course, in many embodiments, the weights may be selected to all equal one.

Various algorithms (e.g., gradient descent learning algorithms) may be used in combination with the neural network algorithm to solve the cost function.

According to the present invention, the solution to the direct problem applied in the above described embodiment with two leaves can be generalized to embodiments with three or more leaves. This may be done when the solution found after applying the above described solution procedure differs too much from the optimal solution. A threshold may be defined to stop the process automatically or the process may be stopped when the designer decides to do so because the gain of the matching specification is small compared to the cost of adding a new antenna element (in terms of both non-recurring expenditures and bill of materials).

As part of the design process of the antenna according to the invention, it may be beneficial to use an electromagnetic simulation tool that uses the eigenmode theory of the combined moment method. See, for example: "A generated expansion for radial and scattered fields" by R.J.Garbacz and R.H.Turpin (IEEE transactions protocols, vol.ap-19, No. 3, p.348 and 358, 5.1971); "the Theory of structural modules for connecting blocks" of R.F.Harrington and J.R.Mautz (IEEE transactions protocols, vol.AP-19, No. 5, p. 622-; "computer of networking modules for connecting blocks" of R.F.Harrington and J.R.Mautz (IEEE transactions protocols, vol.AP-19, No. 5, p. 629-; harrington and J.R.Mautz, "musical models for electronic and magnetic chips" (IEEE transactions applications, AP-20, 2, p. 194, 198, 3. 1972).

Such tools are available in COTS (commercial off the shelf), e.g. FEKO for moment methods (MoM)^TMAnd CST^TM. Such tools allow designing electromagnetic devices and antennas according to their material and geometry descriptions. Such means allow representing the current for each of the resonant modes of the antennaWithout actually transmitting or receiving electromagnetic waves. The selectivity of each of the resonance modes can be evaluated using a figure of merit (null), allowing a fair prediction of the bandwidth for the level of matching at a defined value. A process implemented in one of these tools may be applied at each step of the design method, allowing the values of the different resonance frequencies of the antenna arrangement or parts thereof and the associated electrical performance of each element to be calculated to check compliance with the specifications. The calculation may be performed at the level of the combined antenna arrangement. Once apprised of the present disclosure, one of ordinary skill in antenna design will know how to link the various steps of a simulation to achieve a complete design that matches the specification.

Thus, using such tools, a library of antenna elements with characteristic parameters defined according to the present invention can be constructed, then the susceptance of each element calculated, and in some instances the equations generalized from equations 16, 17 and 18 above solved in an exact manner or in an approximate manner with known sub-optimal costs.

The invention can also be applied to dipole antennas. A dipole antenna is a two-pole antenna in which both poles are excited by a differential generator. The two poles of the dipole antenna are each operated in a fixed state having the same behavior. The dipole antennas each include a structure having a main line, one or more branches, and one or more leaves. In some embodiments of the invention, the two structures are symmetrical.

Accordingly, the examples disclosed in this specification are merely illustrative of some embodiments of the invention. These examples do not in any way limit the scope of the invention as defined by the appended claims.