Linear polarization dual-beam antenna based on holographic tensor impedance modulation metasurface

Abstract

The invention provides a linear polarization dual-beam antenna design based on a holographic tensor impedance modulation metasurface. The metasurface is of a three-layer unit structure which sequentially comprises a lower-layer metal floor, a dielectric layer and an upper-layer circular patch, the circular patch is slotted, and the tensor surface impedance of the unit is jointly determined by the size of the patch and the slotting direction. The array is composed of 31 * 36 units, monopole feed antennas loaded on a metasurface are excited respectively, and excited surface waves are converted into + / -45-degree linear polarization wave beams with high gain and high cross polarization discrimination to be radiated outwards. Compared with a traditional reflection type and transmission type electromagnetic metasurface, an additional space wave feed source does not need to be introduced, and the profile size of the antenna is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface. Background Technique

[0002] Antennas play a crucial role in transceiver systems. In addition to meeting radiation characteristics such as antenna gain and polarization, it is also desired that the antenna has more accurate directivity, a smaller aperture, a lower profile, and can be conformal on more complex structures, which puts higher requirements on the electromagnetic and physical characteristics of the antenna. Existing antennas are difficult to achieve high beam focusing characteristics while controlling the beam polarization characteristics, and need to be improved in terms of profile size, gain, etc.

[0003] Holographic impedance modulation surface antennas have characteristics such as a low profile, high gain, a simple feed network, and good conformal ability. As an extension and innovation of traditional periodic structure leaky wave antennas, holographic impedance modulation surface antennas combine the holographic principle in optics to reproduce the target wave by exciting a holographic interference surface with a reference wave. In terms of implementation, a new type of holographic impedance surface composed of isotropic or anisotropic units is adopted, and the feed source is mostly a monopole antenna and is integrated with the impedance surface, which determines that it has a lower profile and is easy to integrate with active systems. The tensor surface unit can theoretically control the coupling between the surface current and the magnetic field in any direction, so the tensor holographic antenna is superior in electromagnetic wave polarization mode regulation and aperture efficiency. In view of this characteristic, a linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface is designed, and ±45° linearly polarized beams with high gain and high cross-polarization discrimination are radiated by respectively exciting the monopole feed antennas loaded on the metasurface. Summary of the Invention

[0004] The purpose of the present invention is to design a linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface, and ±45° linearly polarized beams with high gain and high cross-polarization discrimination are radiated by respectively exciting the monopole feed antennas loaded on the metasurface.

[0005] To solve the above technical problems, the specific technical solutions of the present invention are as follows:

[0006] In some embodiments of the present application, a linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface is provided, including: two monopole feed antennas, which are respectively located at the central positions of the left half region and the right half region of the metasurface array;

[0007] A holographic tensor impedance modulation metasurface, which is composed of 31×36 periodically arranged units, and each unit includes:

[0008] A dielectric substrate;

[0009] A lower metal floor, covering the lower surface of the dielectric substrate;

[0010] An upper metal patch, which is a circular patch structure, with a slit having a width of 0.6 - 4.4 mm opened at its center, and the direction of the slit is consistent with the principal axis direction of the unit tensor impedance;

[0011] The average surface impedance of the units in the left half of the metasurface array is 207.7 Ω, and the modulation coefficient is 64.9, which is used to radiate a +45° linearly polarized beam;

[0012] The average surface impedance of the units in the right half of the metasurface array is 201.8 Ω, and the modulation coefficient is 63.3, which is used to radiate a -45° linearly polarized beam;

[0013] The monopole feed antenna is integrated with the metasurface through an opening in the backplane. The excited surface wave forms leaky wave radiation due to the impedance discontinuity of the metasurface and is converted into a spatial beam.

[0014] In some embodiments of the present application, the spacing dimension of the upper metal patches is from 0.6 mm to 4.4 mm, corresponding to the unit eigenfrequency covering 4.5 GHz to 4.95 GHz, and the principal axis impedance value is from 191.2 Ω to 272.6 Ω.

[0015] In some embodiments of the present application, the holographic tensor impedance modulation metasurface realizes beam control through the microwave holographic interference principle, specifically:

[0016] The surface wave excited by the monopole feed antenna is used as the reference wave;

[0017] The target space radiation beam is used as the object wave;

[0018] The impedance distribution of the metasurface is determined by the interference hologram of the reference wave and the object wave, and the polarization and direction control of the target beam are realized through the leaky wave radiation mechanism.

[0019] In some embodiments of the present application, the peak gain of the antenna at the 4.9 GHz frequency point is 23.6 dBi and 23.2 dBi, the 20 dB gain bandwidth covers 4.52 GHz to 5.24 GHz, and the cross-polarization discrimination ratio is greater than 20 dB.

[0020] In some embodiments of the present application, the slit direction of the upper metal patch is consistent with the principal axis direction of the tensor impedance, and it is specifically determined by the following method:

[0021] According to the polarization angle ±45° of the target beam, calculate the matching relationship between the surface wave propagation direction and the target wave vector;

[0022] Determine the principal axis impedance value and the slit direction of each unit through the holographic interference formula to realize the precise modulation of the array impedance distribution.

[0023] In some embodiments of the present application, the monopole feed antenna is the inner conductor of the SMA connector, and its insertion position passes through the opening on the backplane and directly reaches the surface of the upper metal patch.

[0024] In some embodiments of the present application, the holographic impedance modulation metasurface is based on the working principle of microwave holography, including: the surface wave radiated by the monopole antenna loaded on the array is used as the reference wave, the target spatial radiation beam to be generated is used as the object wave, and the holographic impedance modulation metasurface generates a holographic interference pattern through different surface impedance distributions after the interference of the reference wave and the object wave; when an excitation is applied to the monopole antenna, the generated surface wave propagates along the surface of the array in the form of a traveling wave, showing the characteristic of exponential decay in the direction perpendicular to the surface of the array. Due to the discontinuity of the surface impedance of the array, leaky wave radiation is formed during the propagation of the surface wave, thereby generating the required target beam.

[0025] In some embodiments of the present application, the holographic impedance modulation metasurface corresponding to the upper metal patch is obtained according to the following steps:

[0026] Perform simulation through the eigenmode solver in CST, set the periodic boundary phase difference φ to simulate the transmission characteristics of incident waves at different angles, and the corresponding phase difference and the tangential propagation constant k of the surface wave t The relationship with the propagation distance L is:

[0027] φ = k t L

[0028] Convert it into the corresponding phase difference φ in the xoy plane x and φ y , then its two-dimensional propagation constant and the corresponding propagation direction θ t are:

[0029]

[0030] θ t = arctan(k y / k x ) = arctan(φ y / φ x )

[0031] By setting the corresponding phase differences φ x , φ y in the two directions in the solver, the wave vector k t of the surface wave propagating in different directions along the surface of the unit can be simulated, and the surface impedance Z corresponding to this propagation direction is:

[0032]

[0033] Among them, k0 is the wave vector of the target wave propagating in free space, a is the size of the unit, and ω is the eigenfrequency calculated by the solver; the surface impedance values corresponding to the upper circular patch under different sizes are calculated respectively for subsequent array matching.

[0034] In some embodiments of the present application, obtaining the array tensor holographic impedance modulation metasurface distribution and the size of the upper metal patch and the slitting angle between adjacent units are set according to the following steps:

[0035] The surface wave radiated by the monopole feed located at the center is:

[0036]

[0037] For the expected radiation beam to be a ±45° linearly polarized beam, the main lobe direction is in the direction of θ angle deviating from the positive x-axis of the plane normal, and the corresponding target field is:

[0038]

[0039]

[0040] Among them, is the distance from the feed to any point on the array surface; since the impedance values of the tensor impedance are different in different directions, its impedance value is a two-dimensional matrix, and the equivalent scalar impedance value Z corresponding to each position on the surface and the source field J surf and the target field E obj The relationship is:

[0041]

[0042] The relationship between its normalized equivalent scalar impedance value Z and the propagation of the surface wave along the antenna surface is

[0043]

[0044] Take the maximum impedance value of the unit during the propagation of the surface wave along each propagation direction as the main axis impedance of the unit. According to the calculated main axis impedance values and their corresponding directions at each position of the array, the unit structure constructed is matched through the mapping relationship between the main axis impedance value and the patch size, and the size of the circular patch and its corresponding slitting direction at different positions of the array are obtained to realize the array design. The interval range of the upper patches is 0.6 mm - 4.4 mm.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows: by loading two monopole feed antennas to radiate surface waves, which are converted into space radiation waves with ±45° polarization via a metasurface, and the array structure of the metasurface is designed according to its surface impedance. A linearly polarized beam with high gain, high aperture efficiency, and high cross-polarization discrimination rate is achieved through the tensor impedance characteristics, and no additional space feed is required, reducing the profile size of the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0047] Figure 1 is a schematic structural diagram of the unit provided by an embodiment of the present invention;

[0048] Figure 2 is a schematic diagram of the variation curves of the eigenfrequency and surface impedance with the patch size in the main axis direction provided by an embodiment of the present invention;

[0049] Figure 3 is a schematic structural diagram of the antenna provided by an embodiment of the present invention;

[0050] Figure 4 is a schematic diagram of the main axis impedance value and main axis direction value corresponding to each unit of the array provided by an embodiment of the present invention;

[0051] Figure 5 is a schematic diagram of the gain curves of two polarization beams provided by an embodiment of the present invention;

[0052] Figure 6 is a schematic diagram of the gain direction at 4.8 GHz - 5.1 GHz provided by an embodiment of the present invention;

[0053] Figure 7 is a schematic diagram of the XPD direction at 4.8 GHz - 5.1 GHz provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] The following combines the drawings and embodiments to further describe in detail the specific embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0055] To better understand the purpose, structure, and function of the present invention, the following further describes the present invention in detail with reference to the drawings.

[0056] Embodiment 1

[0057] The present invention discloses a linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface, which includes two monopole antennas and a holographic tensor impedance metasurface. The metasurface mainly consists of 31×36 units. The surface waves are radiated by two loaded monopole feed antennas and converted into spatial radiation waves polarized at ±45° via the metasurface. The array structure of the metasurface is designed according to its surface impedance. This design aims to achieve linearly polarized beams with high gain, high aperture efficiency, and high cross-polarization discrimination rate through the tensor impedance characteristics, without introducing additional spatial feeds, and reducing the profile size of the antenna.

[0058] The holographic impedance modulation metasurface converts the surface waves excited by two monopole feed antennas into spatial radiation waves, and radiates linearly polarized beams at ±45° respectively by modulating the surface impedance distribution of the array. This device features a low profile, high gain, and high aperture efficiency.

[0059] The metasurface consists of a holographic impedance surface and a feeding monopole, including 31*36 tensor impedance units. Each unit is composed of a dielectric layer, a lower floor, and an upper circular patch structure. The upper circular patch is divided into two semi-circular structures by a slit. The unit size is 16mm×16mm, the height is 5mm, and the F4B dielectric substrate is used with a relative dielectric constant of 2.65. The circular patch sizes of different impedance units are different, and the slit angles are different. The positions of the monopole antennas are located at the centers of the two regions, and holes are opened in this region so that the monopole feeder is inserted from one side of the metal backplane and directly reaches the side of the metal patch.

[0060] The tensor holographic impedance modulation metasurface is realized based on the working principle of microwave holography. Specifically: the surface waves radiated by the monopole antennas loaded on the array serve as the reference waves, and the target spatial radiation beam to be generated serves as the object wave. The holographic impedance modulation metasurface generates a holographic interference pattern through different surface impedance distributions as the interference between the reference wave and the object wave. When an excitation is applied to the monopole antenna, the generated surface waves propagate along the array surface in a traveling wave manner, showing an exponentially decaying characteristic in the direction perpendicular to the array surface. Due to the discontinuity of the array surface impedance, leaky wave radiation is formed during the propagation of the surface waves, thereby generating the required target beam.

[0061] Obtain the surface impedance corresponding to units with different patch sizes according to the following steps:

[0062] Perform simulations through the eigenmode solver in CST, set the periodic boundary phase difference φ to simulate the transmission characteristics of incident waves at different angles, and the corresponding phase difference and the tangential propagation constant k of the surface wave t The relationship with the propagation distance L is:

[0063] φ=k t L

[0064] Convert it into the corresponding phase difference φ in the xoy plane x and φ y , then its two-dimensional propagation constant and the corresponding propagation direction θ t are:

[0065]

[0066] θ t = arctan(k y / k x ) = arctan(φ y / φ x )

[0067] By setting the corresponding phase differences φ x , φ y in the two directions in the solver, the wave vector k t of the surface wave propagating along different directions on the unit surface can be simulated. The corresponding surface impedance Z along this propagation direction is:

[0068]

[0069] where k0 is the wave vector of the target wave propagating in free space, a is the size of the unit, and ω is the eigenfrequency calculated by the solver. Calculate the corresponding surface impedance values of the upper circular patch under different sizes for subsequent array matching.

[0070] Obtain the array tensor impedance distribution and the patch size and the slot opening angle between adjacent units according to the following steps:

[0071] The surface wave radiated by the monopole feed located at the center is:

[0072]

[0073] For the expected radiation beam to be a ±45° linearly polarized beam, its main lobe direction is in the direction where the plane normal deviates from the positive x-axis by an angle θ, and the corresponding target field is:

[0074]

[0075] where is the distance from the feed to any point on the array surface. Since the impedance values of the tensor impedance are different in different directions and its impedance value is a two-dimensional matrix, the relationship between the equivalent scalar impedance value Z corresponding to each position on the surface and the source field J surf and the target field E obj is:

[0076]

[0077] The relationship between its normalized equivalent scalar impedance value Z and the propagation of surface waves along the antenna surface is

[0078]

[0079] Take the maximum impedance value of the unit during the propagation of surface waves in each propagation direction as the principal axis impedance of the unit. According to the calculation, the principal axis impedance values corresponding to each position of the array and their corresponding directions are obtained. The unit structure constructed is matched through the mapping relationship between the principal axis impedance value and the patch size, and the sizes of the circular patches at different positions of the array and their corresponding slotted directions are obtained to realize the array design. The interval range of the upper-layer patches is 0.6 mm - 4.4 mm.

[0080] Appendix Figure 1 Shows the structural dimensions of the unit. Each unit consists of a dielectric layer, a lower-layer floor, and an upper-layer patch. The dielectric is of F4BM265 material, with a relative dielectric constant of 2.65 and a thickness of 5 mm. The upper-layer metal patch is a circular patch with a slot. A slot with a width of 0.6 mm is opened through the center of the circle, and the direction of the slot is consistent with the direction of the principal axis of the tensor impedance corresponding to the unit.

[0081] Appendix Figure 2 Shows the influence of the size of the upper-layer metal patch on the eigenfrequency of the unit and its corresponding surface impedance. The interval distance of the central circular patch varies from 0.6 mm to 4.4 mm. The eigenfrequency of the unit covers 4.5 - 4.95 GHz, covering the entire working frequency band, and its corresponding principal axis impedance value is 191.2 Ω to 272.6 Ω.

[0082] Appendix Figure 3 Shows the processing model of the antenna and its feeding structure. The array structure consists of a holographic impedance surface and a feeding monopole. The positions of the monopoles are located at the centers of the two regions. Holes are opened in this region so that the monopole feeder is inserted from one side of the metal backplane and directly passes through to the side of the metal patch. During operation, the target monopole antenna is excited to radiate surface waves, and the target beam is radiated through the array surface. During actual testing, the inner conductor of the SMA connector is used as the monopole antenna to radiate surface waves.

[0083] Appendix Figure 4 Shows the distribution of the interval sizes and slotted directions of the upper-layer patch units on the array. The designed holographic impedance surface consists of 31×36 units. For the units on the left half of the array surface, a modulation method with an average impedance X = 207.7 and a modulation coefficient M = 64.9 is used to radiate +45° polarized waves; the units on the right half of the array surface use a modulation method with X = 201.8 and M = 63.3 to radiate -45° polarized waves. The relationship between the tensor impedance of each unit, the modulation method, and their geometric positions is:

[0084]

[0085] Calculate the major axis impedance magnitudes and their corresponding direction values at various locations in the array, determine the unit structure at the corresponding position based on the major axis impedance magnitude and the major axis direction from the designed unit library, and construct the array.

[0086] Appendix Figures 5-7 Shows the physical antenna test results and simulation data. When feeding the SMA connector loaded at the center of the left half-plane, the metasurface antenna generates a +45° polarized beam, with a peak gain of 23.6 dBi at 4.9 GHz and a 20 dB gain bandwidth of 4.56 GHz - 5.24 GHz; when feeding the SMA connector loaded at the center of the right half-plane, the radiated -45° polarized beam has a peak gain of 23.2 dBi at 4.9 GHz and a 20 dB gain bandwidth of 4.52 GHz - 5.22 GHz. The test results have higher gain and aperture efficiency compared to traditional scalar impedance metasurfaces, and can achieve polarization control. Throughout the operating frequency band of 4.8 GHz - 5 GHz, the cross-polarization discrimination ratios for both polarizations exceed 20 dB, achieving good polarization characteristics.

[0087] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0088] The terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise stated, the meaning of "plurality" is two or more.

[0089] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0090] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts among the various embodiments can be referred to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the description in the method section.

[0091] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface, characterized in that Comprising: Two monopole feed antennas, respectively located at the central positions of the left half region and the right half region of the metasurface array; A holographic tensor impedance modulation metasurface, composed of 31×36 periodically arranged cells, and each cell includes: A dielectric substrate; A lower metal floor, covering the lower surface of the dielectric substrate; An upper metal patch, which is a circular patch structure, and a slit with a width of 0.6 - 4.4 mm is opened at its center, and the direction of the slit is consistent with the main axis direction of the cell tensor impedance; The average surface impedance of the cells in the left half part of the metasurface array is 207.7Ω, and the modulation coefficient is 64.9, which is used to radiate a +45° linearly polarized beam; The average surface impedance of the cells in the right half part of the metasurface array is 201.8Ω, and the modulation coefficient is 63.3, which is used to radiate a -45° linearly polarized beam; The monopole feed antenna is integrated with the metasurface through a hole in the backplane, and the excited surface wave forms leaky wave radiation through the impedance discontinuity of the metasurface and is converted into a spatial beam.

2. The linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface according to claim 1, characterized in that, The spacing size of the upper metal patches is 0.6 mm to 4.4 mm, the corresponding cell eigenfrequency covers 4.5 GHz to 4.95 GHz, and the main axis impedance value is 191.2Ω to 272.6Ω.

3. A linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface according to claim 1, wherein The holographic tensor impedance modulation metasurface realizes beam control through the microwave holographic interference principle, specifically: The surface wave excited by the monopole feed antenna is used as the reference wave; The target spatial radiation beam is used as the object wave; The impedance distribution of the metasurface is determined by the interference hologram of the reference wave and the object wave, and the polarization and direction control of the target beam are realized through the leaky wave radiation mechanism.

4. The linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface according to claim 1, wherein The gain peaks of the antenna at the 4.9 GHz frequency point are 23.6 dBi and 23.2 dBi, the 20 dB gain bandwidth covers 4.52 GHz to 5.24 GHz, and the cross-polarization discrimination ratio is greater than 20 dB.

5. A linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface according to claim 1, characterized in that, The slit direction of the upper metal patch is consistent with the main axis direction of the tensor impedance, and is specifically determined by the following method: According to the polarization angle ±45° of the target beam, calculate the matching relationship between the surface wave propagation direction and the target wave vector; Determine the main axis impedance value and slit direction of each cell through the holographic interference formula to realize the precise modulation of the array impedance distribution.

6. A linear polarization dual-beam antenna based on a holographic tensor impedance modulation metasurface according to any one of claims 1 to 5, characterized in that, The monopole feed antenna is the inner conductor of the SMA connector, and its insertion position is directly connected to the surface of the upper metal patch through a hole in the backplane.

7. The linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface according to claim 1, wherein The holographic impedance modulation metasurface is based on the working principle of microwave holography, including: the surface wave radiated by the monopole antenna loaded on the array is used as the reference wave, the required target spatial radiation beam is used as the object wave, and the holographic impedance modulation metasurface uses different surface impedance distributions as the holographic interference pattern generated after the interference of the reference wave and the object wave; when an excitation is applied to the monopole antenna, the generated surface wave propagates along the array surface in a traveling wave manner and shows an exponentially decaying characteristic in the direction perpendicular to the array surface. Due to the impedance discontinuity of the array surface, the surface wave forms leaky wave radiation during the propagation process, thereby generating the required target beam.

8. A linearly polarized dual-beam antenna based on a holographic tensor impedance modulation metasurface according to claim 1, characterized in that, Obtain the holographic impedance modulation metasurface corresponding to the upper metal patch according to the following steps: Simulations are carried out through the eigenmode solver in CST. The periodic boundary phase difference φ is set to simulate the transmission characteristics of incident waves at different angles. The corresponding phase difference and the tangential propagation constant k of the surface wave t The relationship with the propagation distance L is: φ = k t L Convert it into the corresponding phase difference φ in the xoy plane x and φ y , then its two-dimensional propagation constant and the corresponding propagation direction θ t are as follows: θ t = arctan(k y / k x ) = arctan(φ y / φ x ) By setting the corresponding phase differences φ in two directions in the solver x and φ y , the wave vector k of the surface wave propagating along different directions on the unit surface can be simulated t , and the corresponding surface impedance Z along this propagation direction is as follows: Among them, k0 is the wave vector of the target wave propagating in free space, a is the size of the unit, and ω is the eigenfrequency calculated by the solver; the surface impedance values corresponding to the upper circular patch under different sizes are calculated respectively for subsequent array matching.

9. The linear polarization dual-beam antenna based on a holographic tensor impedance modulation metasurface according to claim 1, wherein Obtain the array tensor holographic impedance modulation metasurface distribution and the size of the upper metal patch and the slitting angle between adjacent units according to the following steps: The surface wave radiated by the monopole feed located at the center is: For the expected radiation beam to be a ±45° linearly polarized beam, the main lobe direction of which is in the direction of θ angle deviating from the positive x-axis of the plane normal, the corresponding target field is: Among them, is the distance from the feed to any point on the array surface; since the tensor impedance has different impedance values in different directions and its impedance value is a two-dimensional matrix, the equivalent scalar impedance value Z corresponding to each position on the surface and the source field J surf and the target field E obj are related as follows: The relationship between its normalized equivalent scalar impedance value Z and the propagation of the surface wave along the antenna surface is Take the maximum impedance value of the unit during the propagation of the surface wave in each propagation direction as the main axis impedance of the unit. According to the calculated main axis impedance values and their corresponding directions at each position of the array, the unit structure constructed is matched through the mapping relationship between the main axis impedance value and the patch size, and the sizes of the circular patches at different positions of the array and their corresponding slitting directions are obtained to realize the array design. The interval range of the upper patches is 0.6 mm - 4.4 mm.

Images