Antenna loaded with electromechanical resonator
阅读说明:本技术 装载有机电谐振器的天线 (Antenna loaded with electromechanical resonator ) 是由 沃尔特·S·沃尔 赫·J·宋 兰德尔·L·库贝纳 卡森·R·怀特 于 2018-03-31 设计创作,主要内容包括:一种天线系统,包括:至少一个有源元件,所述至少一个有源元件具有用于连接到无线电接收器、发射器或收发器的第一端;和至少一个机电谐振器,所述至少一个机电谐振器与(i)所述至少一个有源元件的至少一部分和所述至少一个有源元件的至少另一部分或(ii)所述至少一个有源元件和所述无线电接收器、发射器或收发器串联连接。所述至少一个有源元件在预期操作频率下表现出电容电抗,并且所述至少一个机电谐振器在预期操作频率下表现出电感电抗,所述至少一个机电谐振器的电感电抗在预期操作频率下抵消或基本抵消至少一个天线元件的电容电抗。(an antenna system comprising at least active elements, said at least 0 active elements having a 1 th end for connection to a radio receiver, transmitter or transceiver, and at least 2 electromechanical resonators, said at least 3 electromechanical resonators being connected in series with (i) at least portions of said at least 4 active elements and at least another portions of said at least active elements or (ii) said at least active elements and said radio receiver, transmitter or transceiver, said at least active elements exhibiting a capacitive reactance at a desired operating frequency and said at least electromechanical resonators exhibiting an inductive reactance at a desired operating frequency, the inductive reactance of said at least electromechanical resonators canceling or substantially canceling the capacitive reactance of at least antenna elements at the desired operating frequency.)
An antenna system, comprising:
a. at least active elements, the at least active elements having a terminal for connection to a radio receiver, transmitter or transceiver, and
b. at least electromechanical resonators, the at least electromechanical resonators being connected in series with (i) at least portions of the at least active elements and at least another portions of the at least active elements or (ii) the at least active elements and the radio receiver, transmitter or transceiver.
2. The antenna system of claim 1, wherein the at least active elements of the antenna system exhibit capacitive reactance at an expected operating frequency, and wherein the at least electromechanical resonators exhibit inductive reactance at the expected operating frequency, the inductive reactance of the at least electromechanical resonators canceling or substantially canceling the capacitive reactance of at least antenna elements at the expected operating frequency.
3. The antenna system of claim 2, wherein the electromechanical resonator exhibits both a series resonance and a parallel resonance, the series resonance and the parallel resonance having different resonant frequencies, and wherein the electromechanical resonator does not resonate at an intended operating frequency of the antenna system.
4. The antenna system of claim 3, wherein of the series resonance and the parallel resonance are at a frequency higher than an expected operating frequency of the antenna system, and the other of the series resonance and the parallel resonance are at a frequency lower than the expected operating frequency of the antenna system.
5. The antenna system of claim 1, wherein the at least electromechanical resonators comprise a two-dimensional array of electromechanical resonators.
dipole antenna having two arms with at least openings in each arm, the at least openings defining at least the and second portions of the arm where the at least openings are located, each opening being occupied by at least electromechanical resonators, the at least electromechanical resonators being connected to the at least the and second portions of the arm whose opening it occupies.
7. The dipole antenna of claim 6, wherein the opening in each arm is electrically occupied by the at least electromechanical resonators.
8. The dipole antenna of claim 6, wherein the opening in each arm is also physically occupied by the at least electromechanical resonators.
9. The dipole antenna of claim 6, wherein each arm has a plurality of openings therein, each of the plurality of openings being occupied by at least electromechanical resonators, the at least electromechanical resonators being connected to portions of the arm to which they are located.
10. The dipole antenna of claim 9, wherein each electromechanical resonator presents a positive reactance across the opening in the arm in which it is located.
11, an antenna comprising an array of dipole antenna elements, each of the dipole antenna elements comprising two arms having at least openings therein, each said opening being occupied by an electromechanical resonator, at least of said dipole antenna elements in said array being adapted to be electrically excited by a radio transmitter, the remaining dipole antenna elements in said array at least partially surrounding said at least of said dipole antenna elements in said array, each electromechanical resonator in said openings presenting positive reactance to those portions of said dipole antenna elements on either side of said opening at an intended operating frequency of said antenna.
[ technical field ] A method for producing a semiconductor device
The present invention relates to the improvement of the efficiency of electrically small antennas.
[ background of the invention ]
Techniques for improving the efficiency of Electrically Small Antennas have been known for many years, but these techniques rely on several different schemes to cancel the capacitive reactance exhibited by Electrically short Antennas (Electrically short Antennas). techniques rely heavily on the use of inductors, such as conventional coil inductors, to load the antenna structure. other techniques suggest the use of negative capacitances, see, for example, Stephen e.sussman-form and Ronald m.rudish, "Non-foster impedance Matching of Electrically Small Antennas", IEEE Transactions on Antennas and amplification, vol.57, No.8, aug.8, pp.2230-2241, and Xu et al, U.S. patent No.9,054,798, entitled "Non-transformer Circuit stabilized antenna", whose efficiency is improved by the use of conventional coil inductors, and the quality factor of these coils is limited by the previously demonstrated high quality of the Electrically short Antennas.
U.S. patent No.8,958,766 to Tolgay Ungan and a. nimo, D.
A paper by Tolgay Ungan and Leonhard M.Reindl (see "A New Family of Passive Wireless RF Harvester based on R-C-Quartz inductors", published in Proceedings of the 43rd European microwave Conference reference) proposes to use a Quartz resonator as an effective high Q inductor to convert the impedance of a 50 Ω antenna to the impedance of a rectifying circuit. However, this patent does not mention the use of these resonators to match the reactance of an electrically small antenna or to load the body of the antenna for the purpose of increasing the radiation resistance. Nor does the patent mention the use of a parasitic antenna or distributed loading of an electromechanical resonator to allow higher power operation.Many locations, such as dense urban areas, forests, and underwater environments, present significant challenges to the reception and transmission of wireless signals. Low frequency electromagnetic wave (<30MHz) is more efficient than high frequencies in penetrating these difficult environments: (>1GHz) are more efficient, but the systems required to generate and receive these electromagnetic waves are typically large, heavy and inefficient, and therefore impractical for many small and/or mobile platforms, the fundamental reason for the large size and inefficiency of these systems is the size of the antenna relative to the wavelength for systems operating in the HF band (3-30MHz) or below100. Alternatively, the electromechanical resonator may be operated between its series and parallel resonances to exhibit a very high Q: (>103) However, due to heating and non-linear effects, these devices are limited in how much power they can handle before, thus limiting their application to receiving systems only.
the purpose of the embodiments is to utilize the highly efficient induced Q present in electromechanical resonators to load small dipole antennas or antenna arrays to improve efficiency beyond that achievable with conventional compact inductors while allowing high power handling2) To achieve a large inductance Q (preferably > 10)3) And enables compact and efficient low frequency antennas for small and mobile platforms.
The proposed invention has dual uses in the commercial world as well, for example, the proposed antenna structure can be utilized on VLF and LF frequencies to develop improved sensors for geological surveying and communication systems for underground environments.
US 8958766B2 does teach the use of electromechanical resonators to implement inductors (for low power rectifiers, rather than electrically small antennas) with higher Q values, however, conventional off-the-shelf resonators (for timing circuits) cannot be used for small transmit antennas because the power that these devices can handle is too low due to non-linearity and thermal effects, so from the prior art, how to use electromechanical resonators such as quartz tuning forks and MEMS devices to improve the efficiency of dipole antennas or dipole antenna arrays while allowing these antennas to handle the high power required for transmit applications, which point is not obvious.
[ summary of the invention ]
In aspects, the present invention provides antenna systems comprising at least 0 active elements, said at least 1 active elements having a th end for connection to a radio receiver, transmitter or transceiver, and at least electromechanical resonators, said at least electromechanical resonators being connected in series with (i) at least portion of said at least active elements and at least another portion of said at least active elements or (ii) said at least active elements and said radio receiver, transmitter or transceiver.
In another aspect, the invention provides a dipole antenna having two arms with at least apertures in each arm, the at least apertures defining at least and a second portion of the arm where the at least apertures are located, each aperture being occupied by at least electromechanical resonators, the at least electromechanical resonators being connected to at least and the second portion of the arm whose aperture it occupies.
In yet another aspect, the invention provides an antenna comprising an array of dipole antenna elements, each of the dipole antenna elements comprising two arms having at least openings therein, each said opening being occupied by an electromechanical resonator, at least said dipole antenna elements in said array being adapted to be electrically excited by a radio transmitter, the remainder of said array at least partially surrounding said at least said dipole antenna elements in said array, each electromechanical resonator in said opening presenting positive reactance to those portions of said dipole antenna elements on either side of said opening at an intended operating frequency of said antenna.
[ description of the drawings ]
Fig. 1a depicts an electrically short dipole antenna loaded with electromechanical resonators.
Figure 1b depicts an electrically short dipole antenna loaded with two electromechanical resonators.
Fig. 1c depicts an electrically short monopole antenna loaded with an electromechanical resonator.
FIG. 2a depicts an embodiment of an electromechanical resonator, which is a quartz shear mode micro-electromechanical system (MEMS) device.
Figure 2b depicts an equivalent circuit of an electromechanical resonator.
Fig. 3 has two simulation graphs for an antenna designed to operate at a frequency of about 67.5kHz in the LF band, the upper graph illustrating the inductance and quality factor (with respect to frequency) of a suitably constructed electromechanical resonator, the lower graph comparing the antenna efficiency with respect to the length of its active element of an embodiment using an electromechanical resonator according to the upper graph with a similar antenna using a prior art (SOA) conventional off-the-shelf (COTS) chip inductor (Q50).
Fig. 4 has two simulation plots completed for an antenna designed to operate at about 1.006MHz in the MF band, the upper plot showing the inductance and quality factor (with respect to frequency) of a suitably constructed electromechanical resonator, and the lower plot comparing the antenna efficiency with respect to the length of its active elements for an embodiment using an electromechanical resonator according to the upper plot and a similar antenna using a prior art (SOA) conventional off-the-shelf (COTS) chip inductor (Q50).
Fig. 5 has two simulation plots completed for an antenna designed to operate at about 31.88MHz in the VHF band, the upper plot showing the inductance and quality factor (with respect to frequency) of a suitably constructed electromechanical resonator, and the lower plot comparing the antenna efficiency with respect to the length of its active element for an embodiment using an electromechanical resonator according to the upper plot and a similar antenna using a prior art (SOA) conventional off-the-shelf (COTS) chip inductor (Q50).
Fig. 6 has two simulation plots completed for an antenna designed to operate at approximately 2.005GHz in the UHF band, the upper plot showing the inductance and quality factor (with respect to frequency) of a suitably constructed electromechanical resonator, and the lower plot comparing the antenna efficiency with respect to the length of its active element for an embodiment using an electromechanical resonator according to the upper plot and a similar antenna using a prior art (SOA) conventional off-the-shelf (COTS) chip inductor (Q50).
Fig. 7 shows a plot of the voltage gain of a 0.05m monopole antenna matched to an MF quartz pull-mode resonator.
Figures 8a and 8b depict embodiments in which the electromechanical resonator is placed in the antenna element along the active element of the antenna rather than at the input end of the antenna element.
Fig. 9 is a graph showing that the efficiency of a 12 inch dipole antenna with a quartz shear mode resonator loaded in the center is superior to the efficiency of the same antenna with a quartz shear mode resonator loaded in the base.
Figures 10a and 10b depict embodiments in which an electromechanical resonator is placed in the antenna element along the active element of the antenna and additionally at the input end of the antenna element.
Fig. 11a and 11b depict embodiments in which an array of electromechanical resonators is placed in the antenna element along the active element of the antenna, instead of a single electromechanical resonator as in the embodiment of fig. 8a and 8b, and fig. 11c depicts an embodiment of an array of electromechanical resonators to be used with the embodiment of fig. 11a and 11 b.
Fig. 12a and 12b depict further embodiments in which a single dipole antenna or a single monopole antenna comprises a thin metal rod or sheet connected to a transmitter, receiver or transceiver, in the case of the dipole antenna embodiment, two thin metal bodies are broken at multiple points along their length.
Fig. 13 depicts embodiments of the present invention in which a center dipole or monopole antenna surrounded by a plurality of parasitic dipoles or monopoles is spaced < lambda/4 from a center element.
[ detailed description ] embodiments
Various modifications and uses of the invention in different applications will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to various embodiments.
In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without limitation to these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present invention.
The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference, unless expressly stated otherwise, all features disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose.
Furthermore, any element in the claims that does not explicitly recite a "means" or a "step" to perform a particular function should not be construed as a "means" or "step" clause as specified in clause 112(f) of 35u.s.c. In particular, the use of "step" or "action" in the claims herein is not intended to invoke the provisions of 35u.s.c.112 (f).
In the embodiments of the invention shown in fig. 1a, the invention includes an
The
The transmitter, receiver or
FIG. 1b depicts an electrically
In another alternative embodiments shown in FIG. 1c,
In these embodiments, tuning of the
The embodiments of fig. 1a-1c illustrate the use of the invention on simple antennas, dipole and monopole antennas, however, the invention may be used with other types of antennas , such as slot antennas, Vivaldi antennas, Yagi-Uda antennas, etc. the invention is particularly useful when the antenna is short-lived where it exhibits a capacitive reactance (whose reactance is negative by way of conventional measured reactance), one skilled in the art will recognize that if the antenna has a reactance, this results in an impedance mismatch between the antenna and the transmitter, receiver or
For handheld transceivers, the size of the antenna may be much larger than the size of the electronic device in the transceiver itself. Thus, reducing the size of the antenna has many advantages (if not otherwise) for the user in terms of user convenience, but reducing the size of the antenna will result in the antenna exhibiting a capacitive reactance and thus an impedance mismatch if measures are taken to deal with the capacitive reactance.
In the following discussion, the ideal case will be discussed in which the reactance of the antenna is "cancelled" or "cancelled" by the
Mathematically, it is easier to talk about the ideal case of eliminating the reactance of an electrically short antenna, but it should be kept in mind that close to elimination (to reduce the VSWR to an acceptable level) is a highly desirable result with the present invention.
TABLE I
The electrical characteristics of the
According to r.c. hansen ("Efficiency and Matching transmissions for inductive Loaded Short Antennas," IEEE Transactions on Communications, vol.com-23, No.4, apr.1975), the radiation Efficiency of an electrically small dipole antenna or a monopole antenna is given by the following equation 1 (equation 1):
wherein R isradIs the antenna radiation resistance, R, of a monopole antennalossIs the ohmic loss, R, of the antennamatchIs the ohmic loss associated with the matching network. For monopole antenna, Rrad=10k2h2Where k is the free space wavenumber, h is the monopole height, Rloss=Rsh/3 π a, where a is the diameter of the conductor, RsIs surface resistivity in ohms per square, and Rmatch=|XaI/Q, wherein XaIs the antenna reactance and Q is the quality factor of the inductor used to match the antenna reactance. Use of low
The conventional matching network of the coil inductor of (a) results in large ohmic losses and poor efficiency for electrically small antennas. Furthermore, as the antenna becomes too small (and thus exhibits a high negative reactance), a very large coil inductor is required to produce the reactance needed for effective matching. The present invention overcomes these limitations by replacing the coil inductor used in the prior art with a high QThe selection of the particular type of
It should also be appreciated that the resonator types suggested in paragraph above and in Table I are merely suggested, and that other electromechanical resonator types may be used instead, particularly when the expected operating frequencies are near the band edges as shown in the table.
TABLE II
Parameter(s)
Value of
C0
2pF
C1
10fF
L1
2474H
R1
248Ω
once these specifications are determined, the resonator design can be determined.for UHF operation, a shear mode resonator will be the best choice, as described above.
Now, to demonstrate the electrically
Fig. 3 has two simulated views for an antenna designed to operate at about 67.5kHz in the LF band using a resonator with BVD parameters listed in the fourth inclusive data column of table I (e.g., the rightmost column). fig. 4 also has two simulated views for an antenna designed to operate at about 1.006MHz in the MF band, the resonator having BVD parameters listed in the third inclusive data column of table I fig. 5 also has two simulated views for an antenna designed to operate at about 31.88MHz in the VHF band, the resonator having BVD parameters listed in the second inclusive data column of table I fig. finally, fig. 6 has two simulated views for an antenna designed to operate at about 2.005GHz in the UHF band, the resonator having BVD parameters listed in the th inclusive data column of table I above.
The inductance value generated at this optimum state can be modified by altering the shape and size of the resonator to match the capacitive reactance of the antenna.
The modal mass is the mass of the spring/mass resonator, which is electrically equivalent to the BVD model of the resonator. Thus, high L1 is equivalent to high modal quality. The modal quality is only weakly determined by the modal constraints and hence by Q. The Q of a particular resonator can be easily changed by changing the geometry of the electrodes and plates. However, to change the modal quality, the dimensions of the resonator need to be changed, which typically results in a different optimum operating frequency.
Although each in fig. 3-5 shows a significant improvement in efficiency if an
It appears that the higher the Q of the
Figure 7 shows the voltage gain curve for a 0.05m monopole antenna matched to an MF quartz pull-mode resonator. The efficiency is shown in fig. 4. It can be seen from the curve that the 3dB bandwidth of the voltage transmission is less than 10 Hz.
In another embodiments, the invention comprises a dipole (see fig. 8a) or monopole (see fig. 8b)
Wherein QLIs the quality factor of the loading inductor, β and α are Hansen-defined constants, RrIs the radiation resistance, X, of an unloaded antennaaIs the reactance of the unloaded antenna.
To demonstrate the effect of loading an electromechanical resonator into an electrically small dipole antenna, a simulation of a 32MHz shear mode resonator was performed in COMSOL simulation software. The parameters of the BVD model extracted from this simulation are given in table III below (and these parameters are also listed in table I above for VHF devices):
TABLE III
Parameter(s)
Value of
Co
0.8pF
C1
5fF
L1
5mH
R1
3Ω
Around 31.9MHz, the resonator exhibits an inductance of 31.5 muh and a high quality factor of 520. Referring to fig. 9, fig. 9 shows the efficiency of a 12 inch dipole antenna with a quartz shear mode resonator loaded in the center versus the same antenna with a quartz shear mode resonator loaded in the base.
In a further embodiment of the present invention (see fig. 10a and 10b), a
In other embodiments of the present invention (see fig. 11a and 11b), a single dipole or monopole antenna may have its thin metal rod or sheet connected to a transmitter, receiver or
In a further embodiment of the invention (see fig. 12a and 12b), a single dipole or monopole antenna comprises two thin metal arms or plates connected to a transmitter, receiver or
In the final embodiment of the invention, a central dipole or monopole antenna is included surrounded by a plurality of parasitic dipoles or monopoles spaced less than λ/4 from the central element (see fig. 13). In the case of a dipole array, the central antenna element and the parasitic element are each composed of two thin metal rods or sheets. In the case of a monopole array, the central antenna element and the parasitic element are each composed of a single metal rod or sheet placed on the ground plane. In dipole and monopole configurations, the central element is connected to a transmitter, receiver or
The antenna element is generally described as "thin (thin)". For example, if the antenna element is telescopic, thinness may be a desirable property so that it can be pulled out of the handheld communication device in a telescopic manner. As is the diameter of the antenna element. The diameter of the whip antenna element of a handheld communication device is typically only about 1/4 inches. However, antenna elements that are thicker and/or have larger diameters may be advantageous from a purely electrical performance perspective and/or from a mechanical adaptability perspective. Thus, in the context of the present invention, it is not required that the antenna element be thin or thick walled or small or large diameter. In practice, the antenna elements preferably have a circular cross-section, but they may have any suitable cross-section. In practice, the antenna element is made of metal.
This concludes the detailed description of the embodiments of the present invention. The foregoing description of the embodiments and methods of making the same has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or method disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
It will be apparent to those skilled in the art that any of these elements, components and steps may be replaced by other elements, components and steps or deleted .
there is disclosed herein at least an antenna system comprising at least 0 active elements, said at least 1 active elements having a 2 th end for connection to a radio receiver, transmitter or transceiver, and at least 3 electromechanical resonators, said at least 4 electromechanical resonators being connected in series with (i) at least parts of said at least 5 active elements and at least another parts of said at least active elements or (ii) said at least active elements and said radio receiver, transmitter or transceiver, said at least active elements exhibiting a capacitive reactance at an intended operating frequency and said at least electromechanical resonators exhibiting an inductive reactance at an intended operating frequency, the inductive reactance of said at least electromechanical resonators canceling or substantially canceling the capacitive reactance of at least antenna elements at the intended operating frequency.
Conception of
Various concepts of the invention are as follows:
conceive of 1, an antenna system comprising at least active elements, said at least 0 active elements having a end for connection to a radio receiver, transmitter or transceiver, and at least electromechanical resonators, said at least electromechanical resonators being connected in series with (i) at least portions of said at least active elements and at least another portions of said at least active elements or (ii) said at least active elements and said radio receiver, transmitter or transceiver.
6, dipole antennas are contemplated having two arms with at least openings in each arm, the at least openings defining at least the th and second portions of the arm where the at least openings are located, each opening being occupied by at least electromechanical resonators, the at least electromechanical resonators being connected to at least the th and second portions of the arm where it occupies the opening.
Concept 8, the dipole antenna of
Concept 9 the dipole antenna of
11, an antenna comprising an array of dipole antenna elements, each of the dipole antenna elements comprising two arms having at least openings therein, each of the openings being occupied by an electromechanical resonator, at least of the dipole antenna elements in the array being adapted to be electrically excited by a radio transmitter, the remaining dipole antenna elements in the array at least partially surrounding the at least of the dipole antenna elements in the array, each electromechanical resonator in the openings presenting a positive reactance to those portions of the dipole antenna element on either side of the opening at an intended operating frequency of the antenna.
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