An ultrathin transmissive / reflective dual-functional metasurface antenna

Abstract

The application discloses an ultrathin transmission / reflection dual-function metasurface antenna, and belongs to the technical field of antennas. The ultrathin transmission / reflection dual-function metasurface antenna comprises an antenna system, the antenna system comprises a feed source and an array composed of a plurality of transmission / reflection units; the feed source is used for transmitting or receiving electromagnetic waves; and the transmission / reflection unit is used for modulating the phase of a reflected wave and the phase of a transmitted wave. In the application, the dual-function metasurface relies on the Huygens resonance, and can realize independent and efficient manipulation of orthogonal polarization transmission waves and reflection waves on a printed circuit board. When the metasurface is applied to the transmission / reflection dual-function antenna, a horn feed source is used to irradiate the entire metasurface from space, and simulation and actual measurement results are consistent, which shows that the transmission array and the reflection array both have good radiation performance. Importantly, the TA / RA dual-function antenna has the advantages of simple production, simple structure and low cost, and realizes as many electromagnetic manipulation functions as possible with the simplest structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antennas, and particularly relates to a super-thin transmission / reflection dual-function metasurface antenna. BACKGROUND

[0002] With the continuous progress of information technology, wireless communication systems are developing towards multi-function and intelligence, and antennas, as an indispensable part of wireless communication systems, also need to meet the requirements of high performance, intelligence and multi-function. In recent years, metasurface structures have been increasingly applied to high-performance antennas and multi-function antennas due to their special electromagnetic properties, to realize wide frequency band, high gain, low profile and small size. In scientific research and engineering application, how to better manipulate electromagnetic waves has attracted more and more researchers' attention. Since the concept of metasurface was first proposed in 2011, it has attracted more and more attention from researchers due to its unique ability to manipulate electromagnetic waves. Metasurface is a two-dimensional form of metamaterial, and is a metasurface with discontinuous interface phase. This metasurface can freely and flexibly manipulate the amplitude, phase and polarization of scattered waves.

[0003] As a new type of high-efficiency transmission metasurface, Huygens metasurface has the characteristic of "zero loss" in theory. It has excellent regulation and control ability for electromagnetic waves. Huygens metasurface can realize the independent regulation and control of electric field and magnetic field, thereby realizing the free regulation and control of electromagnetic waves, greatly expanding the freedom of metasurface in regulating and controlling electromagnetic waves. Huygens metasurface realizes the manipulation ability of transmission wave through adjusting resonant transmission. In particular, through electric dipole induced magnetic dipole, it can excite Huygens resonance in a double-layer metal structure on a dielectric substrate, and compared with the cross-polarization required by metasurface, Huygens metasurface does not have any influence on the polarization of the electromagnetic wave it interacts with, and can be well applied to linear polarization, circular polarization and elliptical polarization. When this Huygens metasurface is applied to a lens antenna, it can exhibit good radiation performance, and has the advantages of light weight, low cost and easy manufacturing.

[0004] In today's application field, single-function antennas have been unable to meet the development status of the world, and the ability to handle concurrent tasks on a single metasurface is attracting more and more attention in the design of multi-function antennas. For example, dual-function lenses and multi-focus lenses also provide a broad platform.

[0005] The utilization of low-frequency wireless spectrum resources has tended to be saturated, while the spectrum resources of millimeter waves are very rich. Designing a dual-function metasurface working in the 28GHz frequency band has great development space and can meet the development needs of future wireless communication systems. At the same time, the transmission-reflection array antenna with only one dielectric substrate structure is more suitable for large-scale manufacturing and industrialization.

[0006] In the research of metasurface antenna design, generally divided into pure transmission and pure reflection two application type antenna, so that the work efficiency is low, and for the whole space target tracking and wireless communication and other specific application scenarios, the transmission / reflection dual functional antenna is particularly important, the traditional solution of dual functional antenna design is to integrate the reflection unit and the transmission unit on a multi-layer FSS super surface, the multi-layer can make the phase shift range of transmission reach 360 degrees, but at the same time, it will make the structure complex, increase the manufacturing cost, also increase the loss, reduce the radiation efficiency.

[0007] The metasurface is usually divided into two types of reflective metasurface and transmissive metasurface, for the reflective metasurface, it is relatively easy to realize high reflectivity and 360 degree phase shift coverage in a single layer of reflection array, but for the transmissive metasurface, it is difficult to realize high transmission and 360 degree phase control in a single layer of transmission array, so how to design the same frequency transmission / reflection unit on the simplest structure is a challenging task.

[0008] The dual functional antenna integrates the transmission unit and the reflection unit on a dielectric substrate, but when different functional structures are integrated on a piece and placed closely, the high coupling problem is brought to the antenna, the functional structures may influence each other, and the high coupling also seriously affects the performance between the dual functions, so reducing the mutual coupling between different unit modules is crucial for the multi-functional antenna, therefore, in the design of dual functional antenna, how to reduce the mutual coupling between different unit modules in the limited space is the key to the application of multi-functional antenna design, generally, the mutual coupling problem between the closely arranged antenna units, that is, the electromagnetic interference problem between the units, has an influence on the gain and the directional diagram of the antenna.

[0009] In the traditional solution of designing the transmission / reflection dual functional array, one is to use two feed sources, the positive feed is used for the transmission array, and the bias feed is used for the reflection array, the other is to use the positive feed, if two horns are used to irradiate the array surface, the design will become complex, if a positive feed horn is used, when the positive feed source irradiates the reflection array, it will cause a certain shielding to the reflected wave, thereby causing the aperture efficiency to decrease, the gain to decrease, the radiation pattern to be distorted and the feed source impedance to be mismatched, how to reasonably adjust the positional relationship between the feed source and the array surface so that the relative gain is increased compared with the positive feed, and the design is simplified.

[0010] Based on this, the present application designs an ultrathin transmission / reflection dual functional super surface antenna to solve the above problems. SUMMARY

[0011] The present application aims at solving the problems in the prior art, i.e., two feed sources are used in the prior design, a normal feed is used for a transmission array, and a bias feed is used for a reflection array, both of which use a normal feed, if two horns are used to irradiate an array surface, the design becomes complex, if a normal feed horn is used, the reflection wave is blocked when the normal feed source irradiates the reflection array, thereby causing a decrease in aperture efficiency, a decrease in gain, distortion of a radiation pattern, and impedance mismatch of the feed source, how to reasonably adjust the positional relationship between the feed source and the array surface to make the relative gain higher than that of the normal feed, and simultaneously simplify the design, and the present application provides an ultrathin transmission / reflection dual-function metasurface antenna.

[0012] In order to achieve the above object, the present application adopts the following technical scheme:

[0013] An ultrathin transmission / reflection dual-function metasurface antenna comprises an antenna system, wherein the antenna system comprises a feed source and an array composed of a plurality of transmission / reflection units.

[0014] The feed source is used for transmitting or receiving electromagnetic waves.

[0015] The transmission / reflection unit is used for modulating the phase of a reflection wave and the phase of a transmission wave.

[0016] As a further description of the above technical scheme:

[0017] The array is a dual-function array, and the array comprises a metal layer and a dielectric plate from top to bottom.

[0018] As a further description of the above technical scheme:

[0019] The polarization directions of the transmission / reflection units are orthogonal, and the polarization directions of the transmission / reflection electromagnetic waves of the antenna and the electromagnetic waves incident on the array surface of the feed source are orthogonal and isolated.

[0020] As a further description of the above technical scheme:

[0021] The metal layer is printed with a transmission and reflection circuit pattern, and the reflection elements and the transmission elements are alternately arranged on the orthogonal polarization metasurface.

[0022] As a further description of the above technical scheme:

[0023] The alternately arranged elements on the metasurface comprise:

[0024] Along the x-axis, the transmission elements are composed of anti-symmetric dipole pairs etched on both sides of a dielectric substrate.

[0025] Along the y-axis, the reflection elements are composed of two symmetric dipoles.

[0026] As a further description of the above technical scheme:

[0027] The medium substrate is F4B, the dielectric constant is 2.2, the loss tan delta is 0.001, and the thickness h is 1.5 mm.

[0028] As a further description of the above technical solution:

[0029] The design of the metasurface is to arrange the reflecting elements and the transmitting elements on both sides of a medium substrate along the orthogonal directions, and the electromagnetic responses of the two orthogonal polarization elements are effectively isolated.

[0030] As a further description of the above technical solution:

[0031] The double-function array should be designed to reduce the area of the patch and the broadband as much as possible to ensure the equivalent capacitance of the two units.

[0032] As a further description of the above technical solution:

[0033] The projected structure length of the double-function array in the orthogonal polarization direction should be as small as possible to reduce the mutual coupling effect.

[0034] As a further description of the above technical solution:

[0035] The feed source design adopts a horn antenna bias feed of 15 degrees.

[0036] As described above, due to the adoption of the above technical solution, the beneficial effects of the present application are:

[0037] In the present application, the double-function metasurface relies on the Huygens resonance, and can realize independent and efficient manipulation of orthogonal polarization transmission waves and reflection waves on a single printed circuit board. When the metasurface is applied to a transmission / reflection dual-function antenna, a horn feed source is used to irradiate the entire metasurface from space, and the simulation and measurement results show that the transmission array and the reflection array both have good radiation performance. Importantly, this TA / RA dual-function antenna has the advantages of simple production, simple structure and low cost, and realizes as many electromagnetic manipulation functions as possible with the simplest structure. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 A schematic diagram of an ultra-thin transmission / reflection dual-function metasurface antenna is provided for the present application;

[0039] Figure 2 A transmission / reflection dual-function metasurface structure diagram in an ultra-thin transmission / reflection dual-function metasurface antenna is provided for the present application;

[0040] Figure 3 A unit schematic diagram of a transmission element in an ultra-thin transmission / reflection dual-function metasurface antenna is provided for the present application;

[0041] Figure 4 A unit schematic diagram of a reflective element in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0042] Figure 5 A transmissive and reflective amplitude schematic diagram of an x-polarized element in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0043] Figure 6 A current distribution schematic diagram of an x-polarized element at 27.9 GHz in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0044] Figure 7 A transmissive and reflective amplitude schematic diagram of a y-polarized element in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0045] Figure 8 A current distribution schematic diagram of a y-polarized element at 27.6 GHz in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0046] Figure 9 A x-polarized transmissive phase and amplitude schematic diagram when lc is fixed at 1.8 mm in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0047] Figure 10 A y-polarized reflective phase and amplitude schematic diagram when la is fixed at 2.2 mm in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0048] Figure 11 A x-polarized transmissive phase and amplitude schematic diagram with la varying in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0049] Figure 12 A x-polarized transmissive phase and amplitude schematic diagram with lc varying in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0050] Figure 13 A y-polarized reflective phase and amplitude schematic diagram with la varying in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0051] Figure 14 A y-polarized reflective phase and amplitude schematic diagram with lc varying in a super-thin transmissive / reflective dual-functional metasurface antenna according to the present application;

[0052] Figure 15A discrete distribution diagram of a transmission phase Δφ1 in an ultrathin transmission / reflection dual-function metasurface antenna according to the present application is provided;

[0053] Figure 16 A discrete distribution diagram of a reflection phase Δφ2 in an ultrathin transmission / reflection dual-function metasurface antenna according to the present application is provided;

[0054] Figure 17 A three-dimensional far-field radiation pattern simulation diagram of a 28GHz frequency band in an ultrathin transmission / reflection dual-function metasurface antenna according to the present application is provided;

[0055] Figure 18 A two-dimensional far-field radiation pattern simulation diagram and a measured diagram in an ultrathin transmission / reflection dual-function metasurface antenna according to the present application are provided;

[0056] Figure 19 An x-polarized beam gain spectrum and antenna efficiency simulation diagram and measured diagram in an ultrathin transmission / reflection dual-function metasurface antenna according to the present application are provided;

[0057] Figure 20 A three-dimensional far-field radiation pattern simulation diagram at 28GHz in an ultrathin transmission / reflection dual-function metasurface antenna according to the present application is provided;

[0058] Figure 21 A two-dimensional far-field radiation pattern simulation diagram and a measured diagram in an ultrathin transmission / reflection dual-function metasurface antenna according to the present application are provided;

[0059] Figure 22 An y-polarized beam gain spectrum and antenna efficiency simulation diagram and measured diagram in an ultrathin transmission / reflection dual-function metasurface antenna according to the present application are provided. DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0061] Please refer to Figures 1-22 The present application provides a technical solution: an ultrathin transmission / reflection dual-function metasurface antenna, comprising an antenna system, wherein the antenna system comprises a feed source and an array composed of a plurality of transmission / reflection units;

[0062] The feed source is used for transmitting or receiving electromagnetic waves.

[0063] The transmission / reflection unit is used for modulating the reflection wave phase and the transmission wave phase.

[0064] Specifically, the array is a dual-function array, and the array comprises a metal layer and a dielectric plate from top to bottom.

[0065] Specifically, the polarization directions of the transmission / reflection units are orthogonal, and the polarization directions of the antenna transmission / reflection electromagnetic waves and the electromagnetic waves incident on the array surface from the feed are orthogonal and isolated.

[0066] Specifically, the metal layer is printed with a transmission and reflection circuit pattern, and the reflection elements and the transmission elements are arranged alternately on the orthogonal polarization metasurface.

[0067] Specifically, the alternately arranged elements on the metasurface comprise:

[0068] Along the x-axis, the transmission elements are composed of anti-symmetric dipole pairs etched on both sides of a dielectric substrate.

[0069] Along the y-axis, the reflection elements are composed of two symmetric dipoles.

[0070] Specifically, the dielectric substrate is F4B, with a dielectric constant εr=2.2, a loss tan δ=0.001, and a thickness h=1.5 mm.

[0071] Specifically, the design of the metasurface is to arrange the reflection elements and the transmission elements on both sides of a dielectric substrate along orthogonal directions, and the electromagnetic responses of the two orthogonal polarization elements are effectively isolated.

[0072] Specifically, in the design of the dual-function array, the area of the patch and the broadband should be reduced as much as possible to ensure the equivalent capacitance of the two units.

[0073] Specifically, in the orthogonal polarization direction, the projected structure length should be as small as possible to reduce the mutual coupling effect.

[0074] Specifically, in the design of the feed, a horn antenna is used with a 15° bias feed.

[0075] The embodiment is specifically:

[0076] When la=2.2 mm and lc=1.8 mm, the transmission and reflection amplitudes in two orthogonal directions are as shown in Figure 3 For x polarization, from Figure 5It can be seen that there is a transmission peak at 27.9GHz, the transmission amplitude is 0.95dB, the transmission amplitude is greater than -1.8dB and the reflection amplitude is less than -5dB in the considered frequency range, which can be explained by the huygens resonance, the incident wave excites the surface current with time delay on the anti-symmetric dipole pair, the time delay makes the surface current in the top and bottom dipoles to be in the same direction and opposite direction alternately, which corresponds to the even mode coupling and odd mode coupling between the surface currents respectively, in other words, the x-polarized element excites the electric resonance and magnetic resonance in turn in the time period, under appropriate conditions, the impedance matching between the electric resonance and the magnetic resonance produces the huygens resonance, Figure 6 The odd mode coupling of the surface current of the x-polarized element at 27.9GHz is shown, in which the strong current distribution of the reverse flow is shown;

[0077] On the contrary, for y polarization, Figure 7 The results show that there is a reflection peak at 27.6GHz, the reflection amplitude is -0.18dB, the transmission inclination also appears at 27.6GHz, in the frequency range of 25.6-29.3ghz, the transmission amplitude is less than -5dB and the reflection amplitude is greater than -1.8dB, which is a typical electric resonance reflection, which can be explained by the current distribution of the y-polarized element at 27.6GHz, as shown in Figure 8 Overall, the metasurface shows good transmission and reflection characteristics under orthogonal polarization respectively;

[0078] In order to facilitate the design of the transmission / reflection dual-functional metasurface, the transmission phase and amplitude are obtained by fixing lc=1.8mm and sweeping la from 1mm to 3mm, and the reflection phase and amplitude are obtained by fixing la=2.2mm and sweeping lc from 0.4mm to 4.4mm, as shown in Figure 9 and Figure 10 It can be seen that the transmission phase reaches 341° for x polarization and the reflection phase ranges from 326° for y polarization;

[0079] In order to verify the polarization independence of the unit, there is almost no EM interaction between the two orthogonal elements when la and lc values change under the excitation of different polarized electromagnetic waves, the phase and amplitude relative to la and lc in two orthogonal directions are shown in Figures 11-14 It can be seen from 11 that for x polarization, the transmission phase shift at 28Ghz is essentially caused by the change of la, and almost does not change with the change of lc, in addition, the x polarization transmission amplitude remains in the range of -0.11dB to -1.8dB, which also almost does not change with lc, as shown in Figure 12 ;

[0080] It can be seen that the y-polarized element also has similar phenomena, from Figure 13It can be found that the reflection phase shift of 28 GHz is essentially dependent on lc rather than la, as Figure 14 shown, the y-polarized reflection amplitude is higher than -3 dB, and only depends on lc rather than la, in general, Figures 11 to 14 The results in show good isolation between the transmission and reflection elements;

[0081] The results of the above simulation show that the dual-functional metasurface has good transmission wave manipulation performance for x-polarization and good reflection wave manipulation performance for y-polarization, and the reflection phase shift has better linear characteristics, which can be predicted that when the dual-functional metasurface is used to process transmission and reflection waves at the same time, the bandwidth of the reflection wave will be wider than that of the transmission wave;

[0082] Based on the above analysis, the phase distribution in the x and y directions can be controlled independently to achieve the dual-functional requirement, the required phase requirement is calculated according to the bias feed function requirement, and the operating frequency f = 28 GHz is selected. The transmission and reflection array elements are circularly symmetric on the aperture plane, and the distance between the feed and the center of the array is called the focal length F, the focal length F = 176 mm. Since the wave paths from the feed to each element are different, in order to realize the in-phase focusing of the transmission and reflection waves of each array, the elements that experience shorter wave paths need to be compensated by more transmission and reflection phase compensation. It is known that different lengths of patches have different resonance frequencies, and for a given center frequency, different sizes of patches have different transmission and reflection phases. The transmission element is located at (m, n) with the center at (0, 0); the reflection element is located at (m+1 / 2, n+1 / 2) with the center at (1 / 2, 1 / 2), and the discrete distribution of the transmission phase Δφ1 and the reflection phase Δφ2 is obtained by the following formula:

[0083]

[0084]

[0085] C is the speed of light in free space, and the metasurface is composed of 33*33 reflection elements and 32*32 transmission elements, which is a circular array with a diameter of 165 mm, as shown in Figure 15 and Figure 16 ;

[0086] The CST electromagnetic simulation software is used for electromagnetic simulation of the metasurface, and the far-field radiation performance of the transmission / reflection is shown in Figure 17 and Figure 18 , as shown in Figure 17 , when the x-polarized beam of the feed source is irradiated on the metasurface with a 15° bias angle, a high directional pencil transmission beam is generated on the other side of the metasurface, and the main beam transmission angle is 15°, which is consistent with the design angle, and the gain reaches 30.14 dBi, which is improved by 15.1 dB compared with the feed gain, showing strong focusing ability;

[0087] on the other hand, Figure 20 The two-dimensional far-field radiation plot of the middle e-plane shows a cross-polarization level of -14 dB, which agrees well with the simulation results. The measured gain of the transmitted beam is 30.26 dBi, and the cross-polarization level is -12 dB. The simulated and measured transmitted beam gain spectra and antenna efficiency are as follows: Figure 21 As shown, the maximum gain in both simulation and measurement occurs at 28 GHz, validating the design strategy. The simulated 3dB gain bandwidth is 26.66-29.19 GHz, or 9.03%, while the measured 3dB gain bandwidth is 26.32-9.3 GHz, or 10.79%. The maximum antenna efficiencies in simulation and measurement are 45.6% and 46.8%, respectively. The simulation results and the measured results are in good agreement, indicating good radiation performance.

[0088] For biased illumination, y-polarization, such as Figure 20 As shown in Figure 21, a high-directional pencil-reflection beam was excited on the same side of the metasurface, with a gain of 30.73 dBi and a cross-polarization level of -18 dB. The measured gain was 30.29 dBi and the cross-polarization level was -17 dB, which agrees well with the simulation results. The simulated and measured maximum antenna efficiencies are 50.5% and 45.7%, respectively. Furthermore, both the simulated and measured 3-dB gain bandwidths completely cover the 26-30 GHz frequency region. Figure 22 As shown, this broadband characteristic stems from the good linearity of the reflection phase.

[0089] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An ultra-thin transmissive / reflective dual-functional metasurface antenna comprising an antenna system, characterized in that, The antenna system comprises a feed source and an array composed of multiple transmissive / refractive units; The feed source is used for transmitting or receiving electromagnetic waves; The transmissive / refractive units are used for modulating the phase of reflected waves and the phase of transmitted waves; The design of the metasurface is to respectively distribute the reflective elements and the transmissive elements on two sides of the dielectric substrate, and the reflective elements and the transmissive elements on the same side are respectively staggered in the X direction and the Y direction; The transmissive elements on two sides of the dielectric substrate are composed of anti-symmetric dipole pairs, and the transmissive elements on two sides of the dielectric substrate are staggered in the X-axis direction and arranged in an array along the X-axis direction; The reflective elements on two sides of the dielectric substrate are composed of symmetric dipole pairs and arranged in an array in the Y-axis direction; The feed source adopts a horn antenna with a bias of 15°, the feed source is a cross-polarized same-frequency feed source, the metasurface generates transmission under X polarization and generates reflection under Y polarization.

2. The ultra-thin transmissive / reflective dual-functional metasurface antenna according to claim 1, wherein, The polarization directions of the transmissive / refractive units are orthogonal, and the polarization directions of the transmitted / reflected electromagnetic waves of the antenna and the electromagnetic waves incident on the array surface of the feed source are orthogonal and isolated.

3. The ultra-thin transmissive / reflective dual-functional metasurface antenna according to claim 1, wherein, The dielectric substrate is F4B, the dielectric constant εr is 2.2, the loss tan δ is 0.001, and the thickness h is 1.5 mm.

Images