阅读说明：本技术 一种扇形波束平面透镜天线 (Fan-shaped wave beam planar lens antenna ) 是由 李海明 徐泽屹 李承张 陈建平 于 2021-08-09 设计创作，主要内容包括：本发明公开了一种扇形波束平面透镜天线,包括：馈源天线和相移表面,其中,所述相移表面能够将三维立体结构介质透镜中非均匀分布的折射率映射为平面透镜表面相移梯度的差异,所述相移表面还包括相移单元。本发明通过8种相移单元代替全部相移值,引入相移梯度因子使得透镜在两个主平面上的聚焦性能形成差异进而形成扇形波束,按照平面透镜各点计算公式得出每个位置所需相移,并将相移单元按规律排列,在简化结构的同时大幅提高了馈源天线的增益,得到的辐射波束为扇形,整体尺寸小、重量轻、易集成、易加工。(The invention discloses a fan-shaped wave beam plane lens antenna, comprising: the phase-shifting surface can map non-uniformly distributed refractive indexes in the three-dimensional stereo-structure dielectric lens into difference of phase-shifting gradients of the surface of the planar lens, and further comprises a phase-shifting unit. The invention replaces all phase shift values by 8 phase shift units, introduces phase shift gradient factors to enable the focusing performance of the lens on two main planes to form difference so as to form fan-shaped wave beams, obtains the phase shift required by each position according to a calculation formula of each point of the planar lens, and arranges the phase shift units according to a rule, thereby greatly improving the gain of the feed source antenna while simplifying the structure, and the obtained radiation wave beams are fan-shaped, and have small integral size, light weight, easy integration and easy processing.)

1. A fan beam planar lens antenna, comprising: the phase-shifting surface (2) is capable of mapping non-uniformly distributed refractive indexes in the three-dimensional stereo-structure dielectric lens into difference of phase-shifting gradients of the planar lens surface, and the phase-shifting surface (2) further comprises a phase-shifting unit.

2. The fan beam planar lens antenna according to claim 1, wherein the feed antenna (1) is a fan beam antenna.

3. The fan-beam planar lens antenna according to claim 1, wherein the phase shift unit further comprises a first conductor (3), a first medium (4), a second conductor (5), a second medium (6) and a third conductor (7) which are sequentially stacked.

4. The fan beam planar lens antenna of claim 3, wherein said phase shift unit includes eight of 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, 315 °, and divides the entire phase shift range 0-360 ° into eight equal parts,

5. the fan beam planar lens antenna according to claim 3 or 4, wherein the first conductor (3), the second conductor (5) and the third conductor (7) have a cross-shaped or rectangular configuration.

6. The fan-beam planar lens antenna according to claim 5, wherein the phase shift surface (2) further comprises major planes, an E plane and an H plane, wherein the E plane is a plane parallel to the direction of the electric field and the H plane is a plane parallel to the direction of the magnetic field.

7. The fan-beam planar lens antenna of claim 6, wherein the phase shift in the H-plane direction is formulated as:

wherein the content of the first and second substances,the phase shift value of the cell representing the coordinates (i, j),

i denotes the coordinates of the cell on the x-axis, which corresponds to the direction of the E-plane,

f denotes the focal length of the lens,

j denotes the coordinate of the cell in the y-axis, which corresponds to the direction of the H-plane,

r represents a phase shift gradient factor.

8. The fan beam planar lens antenna of claim 7, wherein the initial value of the phase shift gradient factor r is 1.

Technical Field

The invention relates to the technical field of antennas in passive devices, in particular to a fan-shaped beam planar lens antenna.

Background

With the popularization and development of wireless communication technology in the fields of transportation, medical treatment, security inspection, and the like, more and more students are focusing on researching high-performance antennas suitable for different application scenarios. The millimeter wave sector beam antenna can radiate a sector beam, has the characteristics of wide coverage range, strong anti-interference capability and the like, and has unique advantages in the fields of scanning, positioning and tracking, medical imaging, anti-collision radar and the like. With the advent of metamaterials and the increase in the level of processing, loading lenses have become an important way to increase the gain of millimeter wave antennas. The optical lens principle provides an idea for an electromagnetic lens, namely spherical waves radiated by a point light source arranged at the focal point of the lens are converted into plane waves with equal phases through the refraction effect of the lens.

In the existing technical scheme, the lens usually adopts a three-dimensional structure such as a dielectric sphere, a cylindrical lens and the like to realize good focusing characteristics, such as a luneberg lens and the like, but the lens also has great limitations, for example, the dielectric lens usually has large volume and weight and is not easy to integrate in a high-frequency circuit, so that the design of a high-performance fan-shaped beam planar lens antenna based on an artificial electromagnetic material has important practical significance.

The two indexes of beam width and antenna gain need to be considered simultaneously when a fan-shaped beam antenna is designed, the prior art cannot meet the design requirements of high gain and wide beam at the same time, and a lens antenna is a solution with good performance, but the fan-shaped beam lens antenna mostly appears in the form of a cylindrical or spherical lens at present, and a planar lens formed by phase shift units better solves the problems of large volume and difficult integration of the lens antenna; the phase shift unit based on artificial electromagnetic material can reach a narrow phase shift range, and the medium thickness is often increased for increasing the phase shift range, so that the lens is bulky and difficult to integrate.

Disclosure of Invention

The invention aims to provide a fan-shaped beam planar lens antenna, which is used for solving the problems that the conventional planar lens antenna has low gain and large volume and is difficult to process and integrate.

The embodiment of the invention provides a fan-shaped beam planar lens antenna, which comprises: the phase-shifting surface can map non-uniformly distributed refractive indexes in the three-dimensional stereo-structure dielectric lens into difference of phase-shifting gradients of the surface of the planar lens, and further comprises a phase-shifting unit.

Further, the phase shift unit further includes a first conductor, a first medium, a second conductor, a second medium, and a third conductor, which are sequentially stacked.

Further, the phase shift unit comprises eight kinds of 0 °, 45 °, 90 °, 135 °, 180 °, 225 °, 270 °, 315 °, and divides the whole phase shift range of 0-360 ° into eight equal parts,

further, the first conductor, the second conductor and the third conductor are in a cross-shaped or rectangular structure.

The invention has the beneficial effects that: the fan-shaped beam planar lens antenna provided by the invention has the following advantages:

1. compared with other fan-shaped beam medium lens antennas, the fan-shaped beam planar lens antenna has higher gain which can reach 32dB at most, the gain of the fan-shaped beam planar lens antenna is improved by 20dB compared with that of a feed source antenna, the gain can be gradually reduced along with the increase of the width of an H-plane beam, and the gain of the feed source antenna is improved by more than 10 dB;

2. the beam width of the fan-shaped beam planar lens antenna provided by the invention is adjustable, by introducing factors, the value of a phase shift gradient factor can be adjusted and introduced according to needs when a planar lens is designed, the beam width on one main plane is narrower and does not change along with the value, while the beam width on the other main plane is increased along with the increase of the phase shift gradient factor, so that a fan-shaped beam is formed;

3. compared with the traditional dielectric lens antenna, the planar lens adopts a structure of a medium and a conductor, is easier to integrate in a microwave circuit, reduces the volume of the medium, reduces the weight of the antenna, can be obtained by etching the surface conductor, has simpler processing technology compared with the procedures of drilling, polishing and the like in the dielectric lens, reduces the processing cost, and can be used for manufacturing the high-frequency lens antenna;

4. the planar lens provided by the invention has flexible design and strong expansibility, and because the planar lens is composed of a plurality of phase shift units, the high-performance phase shift units designed by the invention can obtain wave beams with different shapes according to different arrangement modes, thereby being suitable for various wireless communication systems.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:

fig. 1 is a schematic side view of a fan-beam planar lens antenna according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a phase shift unit according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of transmittance of each planar lens phase shift unit according to an embodiment of the present invention;

FIG. 4 is a schematic phase shift diagram of each planar lens phase shift unit according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of return loss before and after loading a lens of a feed H-plane horn antenna in an embodiment of the present invention;

FIG. 6 is the directional diagrams of the front and back principal planes of the loading lens of the feed H-plane horn antenna in the embodiment of the present invention;

FIG. 7 is a directional diagram of an antenna in the E plane when the phase shift gradient factors r are different;

fig. 8 is a directional diagram of the antenna in the plane E when the phase shift gradient factors r are different.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

In the description of the present specification, the terms "comprising," "including," "having," "containing," and the like are used in an open-ended fashion, i.e., to mean including, but not limited to. Reference to the description of the terms "one embodiment," "a particular embodiment," "some embodiments," "for example," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. The sequence of steps involved in the embodiments is for illustrative purposes to illustrate the implementation of the present application, and the sequence of steps is not limited and can be adjusted as needed.

The embodiment of the invention provides a fan-shaped beam planar lens antenna, wherein a planar lens is manufactured on the basis of an artificial electromagnetic material, the artificial electromagnetic material is an artificial synthetic material or a composite material with extraordinary electromagnetic properties which are not possessed by natural materials, and the artificial electromagnetic material is also called a metamaterial and has the characteristics of small volume, light weight, easiness in integration and easiness in manufacturing. By the conductor-dielectric laminated structure, electromagnetic characteristics that are difficult to realize by natural materials can be easily realized, and the manufacturing cost is reduced.

Fig. 1 is a schematic structural diagram of a fan-beam planar lens antenna according to the present invention, and as shown in fig. 1, the planar lens antenna includes: the phase-shifting lens comprises a feed antenna 1 and a phase-shifting surface 2, wherein the feed antenna 1 adopts a fan-shaped beam antenna, such as an H-plane horn antenna, the phase-shifting surface 2 can map non-uniformly distributed refractive indexes in a three-dimensional stereo-structure dielectric lens into the difference of phase-shifting gradients of a plane lens surface, and the phase-shifting surface 2 further comprises a phase-shifting unit.

The phase shifting surface 2 comprises a number of phase shifting elements with a thickness much smaller than the operating wavelength.

Specifically, the phase shift unit further includes a first conductor 3, a first medium 4, a second conductor 5, a second medium 6, and a third conductor 7, which are sequentially stacked, and since the thickness of the phase shift unit is relatively thin, and the thickness of the phase shift unit is much smaller than the size of other components of the lens antenna, the thickness of the phase shift unit can be ignored in application calculation, that is, the phase shift unit is treated as a planar structure in practical application.

The medium is an ultrathin medium structure, the conductor is a metal resonance structure, the thickness of the phase shift unit can be effectively reduced, and the size parameter of the phase shift unit provides enough design freedom for realizing large-range phase shift coverage of the phase shift unit. The phase shift unit generally adopts a structure in which a double-layer medium and a three-layer conductor are laminated, and in order to realize large-range phase shift, the phase shift unit in the embodiment adopts a structure in which the three-layer conductor and the two-layer medium are arranged at intervals, so that the problem of insufficient phase shift range caused by small medium thickness is solved.

Further, after the medium is selected, the effect of changing the phase of the incident wave can be achieved by changing the shape and size of the conductor, and referring to the schematic diagram of fig. 2, the conductor in this embodiment has a cross-shaped or rectangular structure. In order to reduce the design difficulty and further reduce the processing cost, a limited phase shift unit in a phase shift range of 0-360 degrees is usually adopted to replace all units, and still can maintain the high performance of the planar lens, by adjusting the shape and the size of the conductor layer, the phase shift unit comprises eight types of units, namely 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees and 315 degrees, and divides the whole phase shift range of 0-360 degrees into equal eight parts, namely 22.5 degrees, 67.5 degrees, 112.5 degrees, 157.5 degrees, 202.5 degrees, 247.5 degrees, 292.5 degrees, 337.5 degrees, 360 degrees and 0 degrees, 22.5 degrees and 337.5 degrees, wherein the ranges of 0 degrees, 22.5 degrees and 337.5 degrees are taken as one range, the phase shift unit is adopted in practical application, the phase shift value is in the range, and the phase shift units corresponding to the intermediate values are adopted in the other ranges, the phase shifts falling within the same range may be replaced by the same type of element, i.e. a 45 ° phase shift element is used when the calculated phase shift value is between 22.5 ° and 67.5 °, a 90 ° phase shift element is used when the calculated phase shift value is between 67.5 ° and 112.5 °, and so on, thereby simplifying the overall design and structure of the fan-beam planar lens antenna. Where the invention assigns the upper boundary value of each range to that range if a boundary value occurs, the lower boundary value does not include, for example, a 45 phase shift element if the phase shift value is 67.5.

Furthermore, the distribution of the fan-beam planar lens antenna surface phase shift units is different from that of a common planar lens, and a phase shift gradient factor r is introduced on the basis of compensating the phase of an incident wave, wherein the phase shift gradient factor r causes the phase shift gradient of the lens surface on the E plane and the H plane to be different. The E surface is a plane parallel to the electric field direction, the H surface is a plane parallel to the magnetic field direction, and the electric field direction, the magnetic field direction and the wave vector k form a rectangular coordinate system. In this embodiment, the wave vector k direction is a direction in which the feed antenna points to the center of the lens, the E plane is a horizontal plane, and the H plane is perpendicular to the E plane. Referring to fig. 1, the pattern of the lens antenna is marked with the plane E and the plane H.

The beam widths of the lens antenna on the two main planes are different due to the phase shift gradient difference, the beam width of the H plane of the lens antenna is increased along with the increase of the phase shift gradient change rate factor, the beam width of the E plane of the lens antenna is almost unchanged, and the value of the phase shift gradient change rate factor can be adjusted according to actual needs, so that fan-shaped beams with different beam widths are formed.

In order to make the output beam of the fan-shaped beam planar lens antenna in this embodiment be in a fan shape, it is necessary to make the phase shift gradient changes of the lens on the two main planes of the E plane and the H plane different, the focusing effect on the E plane is the same as that of the pencil beam, for the H plane, a phase shift gradient factor r is added to adjust the distribution of the phase shift along the H plane, and the phase shift formula is:

wherein the content of the first and second substances,the phase shift value of the cell representing the coordinates (i, j),

i denotes the coordinates of the cell on the x-axis, which corresponds to the direction of the E-plane,

f denotes the focal length of the lens,

j denotes the coordinate of the cell in the y-axis, which corresponds to the direction of the H-plane,

r denotes a phase-shift gradient factor, the initial value of which is 1.

When r is 1, the phase shift gradient is the same in the x-axis direction and the y-axis direction, and the phase shift required for each point on the lens is:

according to the above phase shift formula, as the phase shift gradient factor r increases, the phase shift gradient in the y-axis direction becomes slower, the beam widens, and the gain decreases, so that a fan-shaped beam is formed.

To verify the beneficial effects of the present invention, the following experiments were performed: the H-plane horn antenna is selected as a feed source antenna, and the peak gain of the H-plane horn antenna is 12.1dB, the E-plane beam width is 28.5 degrees and the H-plane beam width is 69.1 degrees through simulation.

Referring to the schematic diagrams of fig. 3 to 4, in order to cover a phase shift range by 360 ° and to make the transmission coefficient sufficiently high, the planar lens phase shift unit of the present example is in the form of a double-layer dielectric plus a triple-layer conductor, preferably, for all the phase shift units, the double-layer dielectric of the first dielectric 4 and the second dielectric 6 uses Taconic TSM-DS3 with the same dielectric constant of 3 as a dielectric manufacturing material, and has a size w equal to 2mm and a thickness of 0.25 mm.

Furthermore, the conductor material adopted in the experiment is copper, the first conductor 3 and the third conductor 7 are of structures with the same shape and size, in order to enlarge the coverage range of the phase shift unit, the structures of the 135 ° phase shift unit and the 270 ° phase shift unit are changed to obtain phase shift which is difficult to achieve, in the embodiment, the three-layer conductor structures of the 135 ° phase shift unit and the 270 ° phase shift unit are of the same shape, wherein the three-layer conductor structures of the 135 ° phase shift unit are both cross-shaped, and the three-layer conductor structures of the 270 ° phase shift unit are both rectangular.

Further, in order to ensure that the phase shift range of the phase shift unit is large enough and the transmission coefficient is high enough, the specific parameters of each phase shift unit in this experiment are shown in table 1 below, and in practical applications, each dimension parameter can be designed according to the structure or dielectric material of the phase shift unit, which aims to ensure that the phase shift range of the phase shift unit is large enough and the transmission coefficient is high enough.

Table 1: phase shift unit parameter table

	a1(mm)	b1(mm)	a2(mm)	b2(mm)
					0 DEG phase shift unit	1.1	0.4	1	1.8
45 DEG phase shift unit	1.1	0.2	0.6	0.6
					90 DEG phase shift unit	1.1	0.1	1.3	0.4
135 DEG phase shift unit	1.9	0.1
					180 DEG phase shift unit	1.9	0.4	1.4	0.2
225 DEG phase shift unit	1.2	0.7	1	1.6
					270 DEG phase shift unit	1	1
315 DEG phase shift unit	1.1	0.6	1	1.1

The cross-shaped conductor is formed by vertically crossing two identical rectangles, the formed cross-shaped conductor is of a symmetrical structure, a1 represents the length of the long side of the rectangle forming the cross-shaped conductor, and b1 represents the length of the short side; a2 is the length of the short side of the rectangular conductor and b2 is the length of the long side of the rectangular conductor.

Referring to the schematic diagrams of fig. 5-8, fig. 5 shows the reflection coefficient of the feed antenna, and it can be seen that the reflection coefficient of the planar lens antenna is low in the working frequency band, most energy can pass through the lens, and fig. 6 shows the directional diagrams of the antenna before and after loading the lens on the E plane and the H plane, and it can be seen that the gain of the feed antenna is greatly improved by the planar lens. According to a phase shift formula, when the focal length F is 150mm, different r values are selected, phase shift required by each position is calculated, designed phase shift units are sequentially arranged to form a 76 × 76 array, the total size is 152mm × 152mm, the performance of the lens antenna is simulated by placing the phase center of the feed antenna 1 at the focal point of the planar lens, fig. 7 is a lens antenna E-plane directional diagram under different r values, and fig. 8 is a lens antenna H-plane directional diagram under different r values, and the obtained simulation results are as follows:

when r is 1, the overall gain of the lens antenna is 32.1dB, the beam width of an H plane is 1.5 degrees, and the beam width of an E plane is 1.6 degrees;

when r is 1.15, the overall gain of the lens antenna is 30dB, the beam width of an H plane is 4.1 degrees, and the beam width of an E plane is 1.7 degrees;

when r is 1.5, the overall gain of the lens antenna is 25.7dB, the beam width of an H plane is 12.3 degrees, and the beam width of an E plane is 1.4 degrees;

when r is 2, the overall gain of the lens antenna is 24.2dB, the H-plane beam width is 18.3 °, and the E-plane beam width is 1 °.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.