A Reflective and Transmissive Dual-Functional Common Aperture Vortex Wave Antenna Based on Electromagnetic Metasurface

Abstract

The present invention relates to a reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface, belonging to the technical field of vortex electromagnetic wave antennas. It includes a plurality of vortex wave antenna elements and a feed horn; the vortex wave antenna element includes a reflection component and a transmission component; it also includes a polarization grating component composed of a metal polarization grating and a dielectric substrate, and parallel etched metal strips are evenly distributed on one side surface of the dielectric substrate to form the metal polarization grating; the reflection component is fixedly arranged on the dielectric substrate on one side of the metal polarization grating, and the transmission component is fixedly arranged on the bottom surface of the dielectric substrate; the metal polarization grating is a ground plane for X-polarized waves, used to form the ground of the reflection-type metasurface, and is equivalent to a filter for Y-polarized electromagnetic waves, used to form the vortex wave of the transmission-type metasurface. The reflection-transmission dual-functional co-aperture vortex wave antenna of the present invention can achieve electromagnetic radiation in the whole space.

Description

Technical Field

[0001] The present invention belongs to the technical field of vortex electromagnetic wave antennas, and particularly relates to a reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurfaces. Background Technique

[0002] A vortex electromagnetic metasurface antenna is a device that generates vortex electromagnetic waves and consists of a metasurface structure and a feed source. An electromagnetic metasurface antenna is a two-dimensional form of electromagnetic metamaterial. Its unique two-dimensional planar structure not only retains the functions of electromagnetic metamaterials to control the phase, polarization, amplitude, etc. of electromagnetic waves, but also greatly reduces the processing and manufacturing difficulty. Compared with traditional electromagnetic waves, the vortex electromagnetic wave carrying orbital angular momentum has an additional helical phase factor. The Poynting vector no longer points along the propagation axis but rotates around the propagation axis while advancing. For a vortex wave with a mode number of l, the phase changes by 2πl in one full rotation around the axis. Vortex electromagnetic waves with different mode numbers are orthogonal to each other. Therefore, vortex electromagnetic waves with different mode numbers can be separated at the terminal, enabling mode multiplexing. The inherent orthogonality between vortex waves with different mode numbers makes them widely applicable in fields such as radar stealth, communication, radar detection, radar imaging, and target recognition. Nowadays, the development of vortex electromagnetic metasurface antennas is advancing rapidly and can be mainly divided into reflective vortex metasurface antennas and transmissive metasurface antennas. Currently, most reflective vortex electromagnetic metasurface antennas are composed of metal patches, dielectric substrates, air layers, and ground planes. Among them, the metal patches and dielectric substrates resonate with the incident electromagnetic waves. The role of the air layer is to increase the range of reflection phase shift, and the ground plane serves to reflect electromagnetic waves. The design process of transmissive vortex electromagnetic metasurfaces is more complex than that of reflective ones. It not only needs to consider the range of transmission phase shift but also the magnitude of transmission amplitude to achieve a high propagation efficiency. In addition, besides metasurfaces, spiral phase plates, circular array antennas, etc. can also generate vortex waves. The method of using metasurfaces to generate vortex waves reduces the manufacturing difficulty and processing cost compared with other methods. Traditional metasurface antennas usually can only generate vortex waves with a single mode number and cannot generate vortex electromagnetic waves with multiple mode numbers, which greatly limits their scope of use. Moreover, usually, vortex electromagnetic metasurface antennas can only be single reflective or single transmissive, without combining the two, and can only achieve electromagnetic wave transmission in half of the space, rather than full-space propagation. Transmissive or reflective metasurfaces, taking the plane where the metasurface is located as the boundary, only regulate the electromagnetic fields in the transmission half-space or reflection half-space, leaving the other half-space unused. In the design of low-efficiency (amplitude efficiency < 0.5) metasurface devices, due to the coexistence of multiple modes, such as the co-polarized / cross-polarized electromagnetic fields in the reflection mode or transmission mode, only the same function can be achieved in the transmission and reflection half-spaces of the metasurface, and independent regulation of the transmission half-space and reflection half-space to achieve different functions cannot be realized. Therefore, designing a co-aperture vortex antenna with multiple mode numbers, a simple structure, full-space propagation, and a relatively high purity of vortex wave modes is a problem that needs to be solved currently. Summary of the Invention

[0003] In order to enable the vortex electromagnetic wave antenna to achieve multiple mode numbers and full-space propagation, the present invention proposes a reflective-transmissive dual-functional co-aperture vortex wave antenna based on electromagnetic metasurfaces.

[0004] A reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface includes a plurality of vortex wave antenna units 2 and a feed horn 3; the plurality of vortex wave antenna units 2 are arranged according to the phase required for vortex compensation; the vortex wave antenna unit 2 includes a reflection component 21 and a transmission component 23, the reflection component 21 includes a reflection upper substrate 212, a reflection lower substrate 214 and a foam layer 215 connected in sequence, a small double-arrow patch 211 is provided on the top surface of the reflection upper substrate 212, and a large double-arrow patch 213 is provided on the reflection lower substrate 214; the transmission component 23 includes a transmission upper substrate 233, a transmission middle substrate 234, a transmission lower substrate 235 and a square patch 232 connected in sequence, and elliptical patches 231 are respectively pasted in the middle of the top surface of the transmission upper substrate 233, the top surface of the transmission middle substrate 234, the top surface of the transmission lower substrate 235 and the top surface of the square patch 232; the small double-arrow patch 211, the large double-arrow patch 213, the square patch 232 and the elliptical patch 231 are all metal patches;

[0005] The improvement lies in: it further includes a polarization grating component 22, the polarization grating component 22 includes a metal polarization grating 221 and a dielectric substrate 222, and the dielectric substrate 222 is a polytetrafluoroethylene F4B high-frequency board; a plurality of parallel etched metal strips are evenly distributed on one side surface of the dielectric substrate 222 to form the metal polarization grating 221;

[0006] The reflection component 21 is fixedly arranged on the dielectric substrate 222 on one side of the metal polarization grating 221 of the polarization grating component 22, and the transmission component 23 is fixedly arranged on the bottom surface of the dielectric substrate 222 of the polarization grating component 22;

[0007] The metal polarization grating 221 is a ground plane for X-polarized waves, used to form the ground of the reflective metasurface, and is equivalent to a filter for Y-polarized electromagnetic waves, used for the formation of vortex waves of the transmissive metasurface; the reflection-transmission dual-functional co-aperture vortex wave antenna can realize electromagnetic radiation in the whole space.

[0008] The further technical solution is as follows:

[0009] The gap between adjacent metal strips in the metal polarization grating 221 is 0.1 mm, the length L1 of the metal strip is 14.25 mm, and the width W1 is 0.4 mm.

[0010] The thickness of the dielectric substrate 222 is 0.5 mm.

[0011] The size ratio of the small double-arrow patch 211 to the large double-arrow patch 213 is 0.64.

[0012] The thickness of the foam layer 215 is 3 mm.

[0013] The major axis of the elliptical patch 231 is a fixed value of 10 mm, and the minor axis is 1 - 10 mm. By changing the ratio of the minor axis to the major axis, the transmission phase and transmission amplitude can be adjusted.

[0014] In the square patch 232, the length of the outermost metal frame edge is 14.4 mm, and the length of the inner metal frame is 14 mm.

[0015] The beneficial technical effects of the present invention are embodied in the following aspects:

[0016] 1. The present invention is a co-aperture reflection and transmission dual-functional vortex electromagnetic metasurface antenna. Compared with the traditional single reflection or transmission vortex electromagnetic metasurface antenna, it can achieve electromagnetic radiation in the whole space and solve the problem of single mode number. It is innovatively proposed to use a polarization grating structure as the separation component between the reflection and transmission components. When excited by an x-polarized wave, the polarization grating is equivalent to a ground plane, which can achieve total reflection of electromagnetic waves and reduce energy loss. When excited by a y-polarized wave, it can directly act on the transmission component, and through the phase compensation of the transmission component, a vortex wave of another mode number is generated.

[0017] 2. The patch in the reflection component is a double-layer "double-arrow" type, with specific proportions. The generated reflection phase shift coverage range can not only reach 360°, but also the reflection phase curve is flatter than that of the traditional single-layer structure, and the accuracy requirement for actual processing is lower.

[0018] 3. The transmission component is composed of three-layer dielectric substrates and four-layer metal patch layers. It reduces the loss. By changing the ratio of the minor axis to the major axis of the "elliptical" patch, the transmission phase and transmission amplitude are adjusted. The transmission phase range reaches 334°, and the transmission amplitude is greater than 0.85. The various indicators of the designed co-aperture reflection and transmission dual-functional vortex electromagnetic metasurface antenna show that the antenna has wide application potential in the fields of communication multiplexing, radar detection, etc. Description of the Drawings

[0019] Figure 1 It is the reflection and transmission dual-functional co-aperture vortex wave antenna and the feed horn of the present invention.

[0020] Figure 2 It is the exploded view of the unit of the reflection and transmission dual-functional co-aperture vortex wave antenna.

[0021] Figure 3 It is Figure 2 The exploded view of the reflection component in

[0022] Figure 4 It is Figure 2 The schematic diagram of the polarization grating component structure in

[0023] Figure 5 It is Figure 4 The top view of

[0024] Figure 6 is Figure 2 An exploded view of the transmission component in

[0025] Figure 7 is Figure 1 The elevation view of the reflection-transmission dual-functional common-aperture vortex wave antenna in

[0026] Figure 8 is the reflection phase curve graph of the reflection-transmission dual-functional common-aperture vortex wave antenna unit at 10 GHz.

[0027] Figure 9 is the transmission phase curve graph of the reflection-transmission dual-functional common-aperture vortex wave antenna unit at 10 GHz.

[0028] Figure 10 is the transmission amplitude curve graph of the reflection-transmission dual-functional common-aperture vortex wave antenna unit at 10 GHz.

[0029] Figure 11 is the three-dimensional radiation pattern of the present invention when operating in the reflection state at a frequency of 10 GHz.

[0030] Figure 12 is the three-dimensional radiation pattern of the present invention when operating in the transmission state at a frequency of 10 GHz.

[0031] Figure 13 is the two-dimensional radiation pattern of the present invention when operating in the reflection state at a frequency of 10 GHz.

[0032] Figure 14 is the two-dimensional radiation pattern of the present invention when operating in the transmission state at a frequency of 10 GHz.

[0033] Figure 15 is the phase distribution diagram of the observation plane of the present invention when operating in the reflection state at a frequency of 10 GHz.

[0034] Figure 16 is the phase distribution diagram of the observation plane of the present invention when operating in the transmission state at a frequency of 10 GHz.

[0035] Figures 1-7 In the figure: common-aperture vortex wave antenna 1, vortex wave antenna unit 2, feed horn 3, screw 4, reflection component 21, polarization grating component 22, transmission component 23, small double-arrow patch 211, upper reflection substrate 212, large double-arrow patch 213, lower reflection substrate 214, air layer 215, metal polarization grating 221, dielectric substrate 222, elliptical patch 231, square patch 232, upper transmission substrate 233, middle transmission substrate 234, lower transmission substrate 235. Detailed implementation mode

[0036] The present invention will be further described below in conjunction with the accompanying drawings through embodiments.

[0037] Embodiment 1

[0038] Referring to Figure 1 , a reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface includes a plurality of vortex wave antenna units 2 and a feed horn 3. The feed horn 3 is a 10 dB standard gain pyramidal horn antenna. The feed horn 3 is placed at the center of the metasurface and is 219 mm away from the metasurface. By changing the polarization of the electromagnetic wave radiated by the feed horn 3, different functions and different types of vortex electromagnetic waves can be generated by the metasurface antenna. When the feed horn 3 radiates an x-polarized wave, a vortex wave with a mode number l = +1 is generated after reflection by the metasurface. When the feed horn 3 radiates a y-polarized wave, a vortex wave with a mode number l = 0 is generated after transmission by the metasurface.

[0039] A plurality of vortex wave antenna units 2 are arranged according to the phase compensation required for the vortex; the vortex wave antenna unit 2 includes a reflection component 21 and a transmission component 23. Referring to Figure 3 , the reflection component 21 includes a reflection upper substrate 212, a reflection lower substrate 214 and a foam layer 215 connected in sequence. The thickness of the reflection upper substrate 212 and the reflection lower substrate 214 is 0.8 mm each, and the foam layer is 3 mm. A small double-arrow patch 211 is attached to the top surface of the reflection upper substrate 212. In the small double-arrow patch 211, the length of the rectangular part is 5.76 mm and the width is 1.76 mm, and the height of the triangular part is 1.44 mm and the base is 3.45 mm. A large double-arrow patch 213 is attached to the top surface of the reflection lower substrate 214. The size ratio K of the small double-arrow patch 211 and the large double-arrow patch 213 is 0.64. Referring to Figure 6 , the transmission component 23 includes a transmission upper substrate 233, a transmission middle substrate 234, a transmission lower substrate 235 and a square patch 232 connected in sequence; elliptical patches 231 are respectively attached to the middle parts of the top surfaces of the transmission upper substrate 233, the transmission middle substrate 234, the transmission lower substrate 235 and the square patch 232. The major axis of the elliptical patch 231 is 10 mm and the minor axis is 2 mm. In the square patch 232, the length of the outermost metal frame edge is 14.4 mm and the length of the inner metal frame is 14 mm.

[0040] The small double-arrow patch 211, the large double-arrow patch 213, the square patch 232 and the elliptical patch 231 are all metal patches.

[0041] Referring to Figure 2 , it further includes a polarization grating component 22; referring to Figure 4, the polarization grating component 22 includes a metal polarization grating 221 and a dielectric substrate 222. The dielectric substrate 222 is a polytetrafluoroethylene F4B high-frequency board with a thickness of 0.5 mm. Parallel metal strips are evenly etched on one side of the dielectric substrate 222 to form the metal polarization grating 221. See Figure 5 , the gap between adjacent metal strips in the metal polarization grating 221 is 0.1 mm, the length L1 of the metal strip is 14.25 mm, and the width W1 is 0.4 mm. The metal polarization grating 221 is a ground plane for X-polarized waves, used to form the ground of the reflective metasurface, and is equivalent to a filter for Y-polarized electromagnetic waves, used for the formation of the transmitted metasurface vortex wave.

[0042] See Figure 1 , the reflection component 21 is fixedly installed on the dielectric substrate 222 on one side of the metal polarization grating 221 of the polarization grating component 22 through screws 4, and the transmission component 23 is also fixedly installed on the bottom surface of the dielectric substrate 222 of the polarization grating component 22 through screws 4.

[0043] The co-aperture vortex wave antenna 1 is composed of 13×13 vortex wave antenna elements 2. The design of the co-aperture vortex wave antenna 1 uses the MATLAB-HFSS-API function library to obtain the compensation phase, and then through the VBS script program written in MATLAB, it is automatically modeled by HFSS. From Figure 1 It can be seen that the patches of the reflection component 21 show a certain regular vortex distribution, and the sizes of the patches in the reflection component 21 are different. The reflection component 21 changes the reflection phase by changing the overall lengths of the small double-arrow patches 211 and the large double-arrow patches 213.

[0044] The small double-arrow patches 211, the large double-arrow patches 213, the upper reflection substrate 212, and the lower reflection substrate 213 resonate at a frequency of 10 GHz, and the foam layer 215 is used to increase their reflection phase so that it can meet the phase requirement of a 360-degree coverage range. The metal polarization grating 221 polarizes and separates the electromagnetic waves excited by the feed horn 3, realizes the reflection of the X-polarized electromagnetic waves excited by the feed horn 3, acts as the ground plane of the reflection component 21 of the co-aperture vortex wave antenna 1, and transmits the Y-polarized electromagnetic waves excited by the feed horn 3, providing excitation for the transmission component 23 of the co-aperture vortex wave antenna 1. The four-layer elliptical patches 231, square patches 232, upper transmission substrate 233, middle transmission substrate 234, and lower transmission substrate 235 resonate at a frequency of 10 GHz. Although the transmission phase does not reach the 360-degree coverage requirement, it can still realize the function of generating vortex waves.

[0045] The four-layer elliptical patch 231 of the transmission component 23 exhibits a certain regular vortex distribution, and the sizes of the four-layer elliptical patches 231 in the transmission component 23 are different. The transmission component 23 changes the transmission phase by adjusting the ratio of the short and long axes of the elliptical patch 231 and the reasonable square patch 232.

[0046] See Figure 7 , the dual-functional co-aperture vortex wave antenna is composed of several vortex wave antenna elements 2.

[0047] See Figure 8 , through simulation tests, under the excitation of the x-polarized wave, the reflection phase of the vortex wave antenna element 2 reached 360°, which can better meet the designed functional requirements.

[0048] See Figure 9 , through simulation tests, under the excitation of the y-polarized wave, the transmission phase of the vortex wave antenna element 2 reached 334°. Although it did not reach the requirement of 360°, it can also realize the function of phase compensation.

[0049] See Figure 10 , through simulation tests, under the excitation of the y-polarized wave, the transmission amplitude of the vortex wave antenna element 2 is greater than 0.85, indicating that the loss during the transmission of electromagnetic waves is less.

[0050] See Figure 11 , which is the three-dimensional radiation pattern of the co-aperture vortex wave antenna 1 when it works in the reflection state. It can be seen that when the co-aperture vortex wave antenna 1 works in the reflection state, the gain at the center frequency point of 10 GHz reaches 18.4 dB, and the radiation pattern is upward radiation.

[0051] See Figure 12 , which is the three-dimensional radiation pattern of the co-aperture vortex wave antenna 1 when it works in the transmission state. It can be seen that when the co-aperture vortex wave antenna 1 works in the transmission state, the gain at the center frequency point of 10 GHz reaches 20.7 dB. The electromagnetic wave radiated by the feed horn 3 can pass through the co-aperture vortex wave antenna 1 and play a role in focusing after phase compensation, and the radiation pattern is a downward radiation pencil beam.

[0052] See Figure 13 , which is the two-dimensional radiation pattern of the co-aperture vortex wave antenna 1 when it works in the reflection state. It can be seen that when the co-aperture vortex wave antenna 1 works in the reflection state, the divergence angle of the vortex wave at the center frequency point of 10 GHz is only 15°, and there is a central hole in the beam, corresponding to the phase singularity of the vortex wave.

[0053] See Figure 14 , which is the two-dimensional radiation pattern of the co-aperture vortex wave antenna 1 when it works in the transmission state. It can be seen that when the co-aperture vortex wave antenna 1 works in the transmission state, the side lobe is 15 dB lower than the main lobe.

[0054] See Figure 15 , which is the phase distribution diagram when the co-aperture vortex wave antenna 1 operates in the reflection state. The size of the observation plane is 400 mm × 400 mm, and it is 314 mm away from the upper surface of the co-aperture vortex wave antenna 1. From Figure 15 , it can be seen that when the co-aperture vortex wave antenna 1 operates in the reflection state, the phase distribution rotates 360° around the propagation axis, indicating that a vortex wave with a mode number of l = +1 is generated.

[0055] See Figure 16 , which is the phase distribution diagram when the co-aperture vortex wave antenna 1 operates in the transmission state. The size of the observation plane is 400 mm × 400 mm, and it is 85 mm away from the lower surface of the co-aperture vortex wave antenna 1. From Figure 16 , it can be seen that when the co-aperture vortex wave antenna 1 operates in the transmission state, the phase distribution has the same characteristics as a plane wave, indicating that a vortex wave with a mode number of l = 0 is generated. The simulation results show that the co-aperture vortex wave antenna 1 in this design realizes the expected function.

[0056] Those skilled in the art can easily understand that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface, comprising a plurality of vortex wave antenna elements (2) and a feed horn (3); the plurality of vortex wave antenna elements (2) are arranged according to the phases required for vortex compensation; the vortex wave antenna element (2) includes a reflection component (21) and a transmission component (23), the reflection component (21) includes a reflection upper substrate (212), a reflection lower substrate (214) and a foam layer (215) connected in sequence, a small double-arrow patch (211) is provided on the top surface of the reflection upper substrate (212), and a large double-arrow patch (213) is provided on the reflection lower substrate (214); the transmission component (23) includes a transmission upper substrate (233), a transmission middle substrate (234), a transmission lower substrate (235) and a square patch (232) connected in sequence, and elliptical patches (231) are respectively attached to the middle parts of the top surface of the transmission upper substrate (233), the top surface of the transmission middle substrate (234), the top surface of the transmission lower substrate (235) and the top surface of the square patch (232); the small double-arrow patch (211), the large double-arrow patch (213), the square patch (232) and the elliptical patch (231) are all metal patches; It is characterized in that: It further includes a polarization grating component (22), and the polarization grating component (22) includes a metal polarization grating (221) and a dielectric substrate (222), and the dielectric substrate (222) is a polytetrafluoroethylene F4B high-frequency board; uniformly distributed and parallel etched metal strips are formed on one side surface of the dielectric substrate (222) to form the metal polarization grating (221); The reflection component (21) is fixedly arranged on the dielectric substrate (222) on one side of the metal polarization grating (221) of the polarization grating component (22), and the transmission component (23) is fixedly arranged on the bottom surface of the dielectric substrate (222) of the polarization grating component (22); The metal polarization grating (221) is a floor for the X-polarized wave and is used to form the ground of the reflective metasurface, and is equivalent to a filter for the Y-polarized electromagnetic wave and is used for the formation of the transmitted metasurface vortex wave; the reflection-transmission dual-functional common-aperture vortex wave antenna can realize electromagnetic radiation in the whole space.

2. The reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface according to claim 1, characterized in that: The gap between adjacent metal strips in the metal polarization grating (221) is 0.1 mm, the length L1 of the metal strip is 14.25 mm, and the width W1 is 0.4 mm.

3. The reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface according to claim 1, characterized in that: The thickness of the dielectric substrate (222) is 0.5 mm.

4. The reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface according to claim 1, characterized in that: The size ratio of the small double-arrow patch (211) to the large double-arrow patch (213) is 0.

64.

5. The reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface according to claim 1, characterized in that: The thickness of the foam layer (215) is 3 mm.

6. The reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface according to claim 1, characterized in that: The major axis of the elliptical patch (231) is a fixed value of 10 mm, and the minor axis is 1 - 10 mm. The transmission phase and transmission amplitude are adjusted by changing the ratio of the minor axis to the major axis.

7. The reflection-transmission dual-functional co-aperture vortex wave antenna based on electromagnetic metasurface according to claim 1, characterized in that: In the square patch (232), the length of the outermost metal frame edge is 14.4 mm, and the length of the inner metal frame is 14 mm.

Images