A design method of a Ku-band metasurface phased array antenna matching layer

Abstract

The application discloses a design method of a Ku-band metasurface phased array antenna matching layer, establishes a non-full-array antenna model, extracts impedance parameters of a phased array antenna array surface under different frequencies and different scanning states, takes the impedance parameters as boundary conditions, preliminarily optimizes the matching layer, and obtains initial parameters of a matching layer structure; according to an actual phased array antenna periodic structure, the initial parameters of the matching layer structure are verified and optimized to obtain final parameters of the matching layer structure. Compared with the prior art, the application can quickly obtain characteristics of an antenna array surface with less resources, and obtain related parameters of a matching antenna, and finally completes the optimization design of the antenna matching layer.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and specifically relates to a design method for a matching layer of a Ku-band metasurface phased array antenna. Background Technology

[0002] Traditional phased array antennas, especially active phased array antennas, achieve beam scanning primarily by adjusting the phase of the phase shifter in the channel of the corresponding radiating element, thereby changing the feed phase of the antenna element. Each antenna element has its own unique feed network, and the position of the antenna element on the array surface is periodic, thus allowing for matching design of individual antenna elements. However, for metasurface phased array antennas, traveling wave feeding is used, each radiating element does not have an independent feed network, and beam scanning is achieved by directly controlling the phase of the radiating element. Matching is often done externally to the radiating element, making it impossible to design matching designs for the feed network of the radiating element itself.

[0003] Therefore, design methods for individual elements cannot be applied to the matching design of phased array antennas. Furthermore, because metasurface phased array antennas, especially those based on glass-based liquid crystals, involve numerous microstructures during simulation design, simulating the feed network and antenna array using traditional simulation verification methods would consume significant computational resources and time, making the overall antenna design and implementation quite difficult. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention aims to provide a design method for the matching layer of a Ku-band metasurface phased array antenna. Based on the actual architecture of the metasurface phased array antenna surface and the feeding network, the characteristic parameters of the antenna surface are used as boundary conditions. Under these boundary conditions, the initial parameters of the matching layer are obtained. These initial parameters are then applied to a specific antenna structure for fine-tuning and optimization, thereby obtaining the final parameters of the matching layer structure to achieve the matching design of the phased array antenna.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A design method for the matching layer of a Ku-band metasurface phased array antenna includes the following steps: Step 1: Establish a non-full-array antenna model and extract the impedance parameters of the metasurface phased array antenna array at different frequencies and scanning states. This step establishes an appropriate model based on the physical structure of the antenna array and, based on this, analyzes the radiation performance parameters of the antenna array under different states. Specifically, the radiation performance parameters refer to the impedance parameters.

[0006] Step 2: Using the impedance parameters as boundary conditions, perform preliminary optimization on the matching layer to obtain the initial parameters of the matching layer structure. This step uses the impedance parameters of the antenna array as boundary conditions, establishes a matching layer model according to requirements, and calculates the initial parameters of the matching layer structure.

[0007] Step 3: Based on the actual periodic structure of the metasurface phased array antenna, verify and optimize the initial parameters of the matching layer structure to obtain the final parameters of the matching layer structure. This step establishes an overall model of the actual antenna array structure and the matching layer, and analyzes and optimizes the matching layer within the overall model to obtain the final design values.

[0008] In one embodiment, the non-full-array antenna model is a periodic structure model established based on the distribution of radiating elements. This model is built by selecting a portion of the radiating elements in the array. The model is distributed periodically throughout the array, possessing periodic boundaries and exhibiting radiation characteristics consistent with the full array. The non-full-array periodic model requires less computation during analysis and allows for rapid acquisition of relevant characteristics. The periodic structure model established in this invention includes various types of radiating element structures and local feeding structures. This local feeding structure is a traveling-wave feeding structure, located below and closely adjacent to the array's radiating structure composed of radiating elements. The traveling-wave feeding structure has feeding ports at both ends in the energy propagation direction, and two sides parallel to the energy propagation direction are magnetic boundaries. These magnetic boundaries satisfy the boundary conditions for the electromagnetic field within the traveling-wave feeding structure. Since the radiating element is composed of multiple radiating slots in different states, the four sides of the radiating element in the periodic structure model are periodic boundaries. Specifically, the four sides of the radiating element are two pairs of parallel planes, with one plane as the primary boundary and the other as the secondary boundary in each pair. A pair of primary and secondary boundaries constitutes a periodic boundary in one direction, and two pairs of periodic boundaries constitute periodic boundaries in two directions. The feed port is taken as the corresponding wave port, and the end of the radiation space adjacent to the upper part of the periodic boundary is taken as the Floquet port.

[0009] Specifically, in a traveling-wave fed structure, electromagnetic waves propagate in TEM mode. In the fed structure model, the two sides aligned with the energy transmission direction are parallel to the electric field direction; therefore, these two sides are designated as magnetic boundaries. The antenna array within the periodic boundary is a repeating unit within the entire antenna array; thus, the entire array can be obtained by expanding outwards through this repeating unit. The periodic structure is determined by defining the master-slave relationship of the four sides when defining the periodic boundary. Different scanning states refer to the beam pointing angle, i.e., the scanning angle. The frequency response of the antenna radiating elements and the array formed by the radiating elements is not completely consistent. The impedance of the antenna array at different frequencies under the required scanning angle is the main characteristic of the antenna array.

[0010] In one embodiment, the Floquet port reference is adjusted to the array plane where the corresponding radiating element is located, and the impedance parameter is extracted using the following formula: in and The antenna surface impedances are for TE mode and TM mode, respectively. For free space wave impedance, The scanning angle, Let be the reflection coefficient of the Floquet port during H-plane scanning. Let be the reflection coefficient of the Floquet port during E-plane scanning.

[0011] In one embodiment, step 2 uses a periodically distributed regular metal pattern on a dielectric substrate as the basic model of the matching layer. Each metal pattern is a radiating element. The matching layer model is established according to the minimum size of the radiating element distribution period. A plane with the same size as the matching layer is established vertically below the matching layer model at a certain distance. The plane is assigned the equivalent impedance of the phased array antenna surface. The plane and the matching layer model together form the required model. The four sides of the required model are assigned periodic boundary conditions, and the top and bottom end faces are assigned Floquet ports. In this way, the S-parameters of the Floquet ports are initially optimized to obtain the initial parameters of the matching layer structure.

[0012] In one embodiment, establishing a matching layer model according to the minimum size of the radiation unit distribution period means including the minimum repeating unit of the matching layer periodic structure in the matching layer model to reduce the size of the model and facilitate rapid analysis and calculation.

[0013] In one embodiment, the method for initially optimizing the Floquet port S-parameters to obtain the initial parameters of the matching layer structure is as follows: By adjusting different structural parameters of the matching layer and calculating the values ​​of the Floquet port S-parameters at the required frequency and scan angle, the structural parameters of the matching layer are considered satisfactory when the values ​​of the Floquet port S-parameters at the required frequency and scan angle meet the requirements. Specifically, adjusting the different structural parameters of the matching layer can follow these rules: adjusting the spacing between different layers to ensure the overall bandwidth meets the requirements, and adjusting the internal parameters of a single layer to ensure the matching layer operates at the required frequency with good matching performance.

[0014] In one embodiment, step 3 involves constructing an array surface model of the actual metasurface phased array antenna and introducing the matching layer model initially optimized in step 2 to obtain an overall model. This overall model is then used for analysis, verification, adjustment, and optimization.

[0015] In one embodiment, the array surface model of the actual metasurface phased array antenna is a periodic structure and includes multiple or even all types of radiating element structures, and the distribution of radiating elements is consistent with the distribution of radiating elements in the actual phased array antenna array surface; the matching layer model is a periodic structure and adopts the initial parameters of the matching layer structure.

[0016] In one embodiment, the matching layer model is introduced to obtain a holistic model, as follows: Take the least common multiple of the periodic structure size of the array surface model and the periodic structure size of the matching layer model to make the two models the same size; The overall model is established by vertically aligning the array model and the matching layer model; the overall model is a cuboid, and the spacing between the array and the matching layer is consistent with the spacing between the matching layer and the plane in step 2. The four sides of the overall model are periodic boundaries, and the top and bottom ends are Floquet ports.

[0017] In this embodiment, since the plane projection of the array model is rectangular and the plane projection of the matching layer model is rectangular, the array model and the matching layer model established by taking the common multiple of the corresponding side lengths of the two rectangles are the same size, so that the two models can be easily integrated into an overall model containing the matching layer and the radiating elements.

[0018] In one embodiment, the analysis, verification, and optimization are implemented as follows: The overall model is calculated and adjusted to ensure that the Floquet port S-parameters meet the requirements at the desired frequency and scan angle. Specifically, calculations are performed on the overall model including the array and matching layer. Based on the calculation results, the relevant parameters of the matching layer are fine-tuned and calculated. This process is repeated until the port S-parameters meet the requirements at both the desired frequency and scan angle. At this point, the structural dimensions of the matching layer are the final parameters of the matching layer structure.

[0019] Compared with the prior art, the beneficial effects of the present invention are: For metasurface phased array antennas, due to their unique array surface and feeding structure, it is impossible to analyze the radiation and matching characteristics of individual antenna elements using conventional analysis methods to obtain array surface characteristics. Furthermore, the large and complex array size makes it impossible to analyze the entire array surface using existing electromagnetic analysis software. This invention, however, constructs a non-full-array antenna model, extracts the array surface parameters of the Ku-band metasurface phased array antenna, obtains the initial parameters of the matching layer, and optimizes the matching layer. This allows for the rapid acquisition of antenna array characteristics with fewer resources, leading to the determination of relevant matching antenna parameters and ultimately the optimized design of the antenna matching layer. Attached Figure Description

[0020] Figure 1This is a flowchart of the design method for the matching layer of the metasurface phased array antenna of the present invention.

[0021] Figure 2 This is a diagram of a model for extracting surface parameters of a metasurface phased array antenna in one embodiment of the present invention.

[0022] Figure 3 This is a model diagram for obtaining the initial parameters of the matching layer in an example of the present invention.

[0023] Figure 4 This is a model diagram for verifying and adjusting the matching layer structure parameters in an example of the present invention.

[0024] Figure 5 This is a matching effect diagram of the matching layer in a specific embodiment of the present invention at 11~13.5GHz. The horizontal axis is frequency in GHz and the vertical axis is gain in dB.

[0025] Figure 6 This is a matching effect diagram of the matching layer in a specific embodiment of the present invention at 13.5~15.5GHz. The horizontal axis is frequency in GHz and the vertical axis is gain in dB. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] For Ku-band phased array antennas, especially metasurface phased array antennas, the special method of phase control of the radiating elements causes them to operate in the non-resonant region, resulting in low efficiency. To improve the efficiency of this type of phased array antenna, a matching layer is needed to match the antenna array surface. Traditional phased array antenna elements have independent feed structures. By optimizing the active standing waves (VSWR) at the ports of the antenna elements and their independent feed structures in the array environment during the design phase, an ideal antenna element can be obtained. Therefore, the structural parameters of the antenna element can be obtained through preliminary optimization of the active VSWR at the ports of the antenna elements in the periodic boundary. However, the feed network of metasurface phased array antennas is a traveling wave structure, and each radiating element does not have an independent feed structure. Therefore, it is more difficult to match the antenna array surface under the conditions of the feed network or a single radiating element.

[0028] To address this, this invention proposes a design method for matching the array surface of a metasurface phased array antenna. This method, targeting Ku-band phased array antennas, obtains the array surface characteristic parameters of the metasurface phased array antenna. Using these parameters as boundary conditions, it performs preliminary optimization on the corresponding matching layer to obtain initial parameters for the matching layer structure. These initial parameters are then verified within the overall model, and finally adjusted to obtain the final parameters for the matching layer structure.

[0029] like Figure 1 As shown, the design method for the matching layer of the Ku-band metasurface phased array antenna of the present invention includes three main steps: Step 1: Extraction of metasurface phased array antenna array parameters.

[0030] Metasurface phased array parameter extraction refers to obtaining the relevant radiation characteristic parameters of the metasurface phased array antenna under different scanning states and different operating frequencies based on the actual antenna array. In this invention, it specifically refers to impedance parameters.

[0031] The antenna model required in this step is a non-full-array antenna model, which is a periodic structure model established based on the distribution of radiating elements. Considering the potential influence of the feed network, this periodic structure model includes various types of radiating element structures and local feed structures. The local feed structure is a traveling wave feed structure, located below and closely adjacent to the array radiating structure composed of radiating elements. The traveling wave feed structure has feed ports at both ends in the energy propagation direction, and two sides parallel to the energy propagation direction as magnetic boundaries. The four sides of the radiating elements in the periodic structure model are periodic boundaries. The feed ports are defined as the corresponding wave ports, and the upper end of the radiation space adjacent to the periodic boundaries is the Floquet port.

[0032] In practical applications, considering the periodic distribution of the antenna array of the actual radiating element, such as... Figure 2 As shown, the radiating element 2 of the metasurface antenna array 1 includes three types of radiating slots: short slots 21, medium-length slots 22, and long slots 23. These three types of radiating slots operate in different frequency bands. Specifically, five short slots 21 operate at high frequencies, six long slots 23 operate at low frequencies, and five medium-length slots 22 operate at the center frequency. The operating frequency can cover the required operating frequency band for Ku. The radiating slots are located between the upper and lower glass layers. Below the lower glass layer is a corresponding slow-wave medium, and below the slow-wave medium is a metal boundary. At both ends of the energy transmission direction on the side of the slow-wave medium are two excitation ports 3, and in the other two directions on the side are magnetic boundaries 4. Above the upper glass layer is a radiating space. Extending a specific length within the radiating space region above the upper glass layer forms a cuboid space. The upper surface of this cuboid is a Floquet port 6, and the four sides are periodic boundaries 5.

[0033] By analyzing the reflection coefficients of Floquet extending downwards to the antenna aperture under different conditions, the phased array antenna surface parameters are extracted using the following formula: in and The antenna surface impedances are for TE mode and TM mode, respectively. For free space wave impedance, The scanning angle, Let be the reflection coefficient of the Floquet port during H-plane scanning. Let be the reflection coefficient of the Floquet port during E-plane scanning.

[0034] In one embodiment of the present invention, the non-full array antenna model has a rectangular periodic structure in the radiating part, and the distribution of radiating elements in the periodic structure is consistent with the distribution in the actual array. Its local feed network port is the corresponding wave port, and the port above the radiation space is the Floquet port. The impedance parameters of the phased array antenna are obtained by analyzing the reflection characteristics of the Floquet port at the phased array antenna array.

[0035] Step 2: Obtain the initial parameters of the matching layer structure.

[0036] The initial parameters of the matching layer structure are obtained by using the obtained impedance parameters of the metasurface phased array antenna as boundary conditions to perform preliminary optimization of the matching layer structure.

[0037] This step involves the basic model of the matching layer and the equivalent impedance plane for the impedance parameters of the metasurface phased array antenna. Specifically, a periodically distributed regular metal pattern on a dielectric substrate is used as the basic model of the matching layer, with each metal pattern representing a radiating element. The matching layer model is established according to the minimum size of the radiating element distribution period, and this model contains the minimum repeating element of the periodic structure of the matching layer. A plane with the same size as the matching layer is established vertically below the matching layer model at a certain distance. This plane is assigned the equivalent impedance of the metasurface phased array antenna, and the plane and the matching layer model together form the desired model. Periodic boundary conditions are assigned to the four sides of the desired model, and Floquet ports are assigned to the top and bottom end faces. This is used to initially optimize the Floquet port S-parameters to obtain the initial parameters of the matching layer structure. Specifically, by adjusting the structural parameters of different matching layers and calculating the values ​​of the Floquet port S-parameters at the required frequency and scanning angle, the structural parameters of the matching layer at this point, which meet the requirements at the required frequency and scanning angle, are the required initial parameters.

[0038] In practical applications, refer to Figure 3 As shown, the matching layer 7 is a single or multi-layer rectangular plane, including square copper patches 71 distributed on one side of the dielectric substrate 72. These square copper patches 71 are distributed in a periodic structure with a subwavelength interval. The square copper patches 71 are processed onto the surface of the dielectric substrate 72 using PCB etching technology. The equivalent impedance plane 8 is also a rectangular plane, and its size is the same as that of the matching layer 7. The periodic structure formed by the collinear normals of the matching layer 7 and the equivalent impedance plane 8, arranged in parallel at certain intervals, constitutes the required model. The model has a periodic boundary 9 around its sides, with the four faces representing the master and slave boundaries, and Floquet port 10 and Floquet port 11 at the two ends of the normal direction.

[0039] By adjusting the relevant parameters of matching layer 7 (mainly the insertion loss between Floquet port 2 10 and Floquet port 3 11 in the model, or the reflection coefficient of a single port), the Floquet reflection at the specified frequency and scanning angle is made to meet the required requirements. At this point, the relevant parameters of the matching layer structure (mainly including the spacing between matching layer 7 and the equivalent impedance plane 8, the size of the square copper patches 71, the spacing between the square copper patches 71, and the thickness of the dielectric substrate 72, etc.) are the required parameters. This process is more efficient because it uses the plane containing the antenna array impedance parameters instead of the actual antenna array, but the accuracy is reduced, and further verification and adjustment are needed in subsequent steps.

[0040] Step 3: Verification and adjustment of the final parameters of the matching layer structure.

[0041] The optimization and adjustment of the matching layer structure parameters are based on the actual metasurface phased array antenna periodic structure. The initial parameters of the matching layer structure are verified and optimized to obtain the final parameters of the matching layer structure.

[0042] Specifically, this step requires first constructing the array surface model of the actual phased array antenna, and then introducing the matching layer model preliminarily optimized in step 2 to integrate them into a whole model. This whole model is then used for analysis, verification, adjustment, and optimization.

[0043] This step primarily involves verifying and adjusting the initial parameters of the acquired matching layer structure. The model established in this process comprises two parts. One part is the array surface model of the actual metasurface phased array antenna. This model has a periodic structure and includes various types of radiating element structures. The distribution of the radiating elements is consistent with the distribution of radiating elements in the actual phased array antenna array surface. This periodic structure contains the minimum period of the actual array surface, and the shape of the array surface is preferably rectangular. The other part is the matching layer model using the initial parameters of the matching layer structure. This matching layer model also has a periodic structure, and its size is consistent with the periodic structure of the array surface. Furthermore, its period contains an integer multiple of the minimum period of the matching layer.

[0044] Since the periodic dimensions of the phased array antenna array surface periodic structure model and the matching layer model are generally inconsistent, a common multiple of the periodic structure dimensions of the array surface model and the matching layer model can be used to make the two models the same size.

[0045] The frontal array model and the matching layer model are aligned vertically at their edges, with the gap between them matching the same as the spacing between the matching layer and the plane in step 2, forming a unified model. This unified model is a cuboid with periodic boundaries on all four sides and Floquet ports on the top and bottom ends. Using Floquet ports at both ends facilitates adjustment of the excitation wave polarization, which verifies the matching characteristics of the matching layer for multiple polarizations. The initial parameters of the matching layer are calculated and analyzed using this model, and adjustments are made to obtain the final matching layer parameters.

[0046] Specifically, the overall model is calculated and adjusted so that the port S-parameters meet the requirements at the required frequency and scanning angle. At this point, the structural dimensions of the matching layer are the final parameters of the matching layer structure.

[0047] In one specific embodiment of the present invention, the surface metamaterial metaphased array antenna operating in the Ku band is fed by a radial line waveguide, and the established model includes a periodic structure composed of radiating elements 2 and matching layers 7, as shown below. Figure 4As shown. The distribution of the radiating element 2 is consistent with that of the metasurface antenna array 1. The outer contour of the periodic structure of the radiating element 2 is rectangular, containing three types of radiating elements, i.e., a total of 16 radiating slots as shown in the figure. These radiating slots are located between the upper and lower glass layers and are arranged in a periodic structure as required. A periodic model is established through this glass, the three types of radiating slots located inside it, and the local traveling wave waveguide, and the radiation impedance of the phased array antenna array is extracted. A matching layer 7 is located at a certain distance above the radiating slots. The outer contour of the matching layer 7 is aligned with the outer contour of the radiating element 2 and has the same size as the outer contour of the periodic structure of the radiating element 2. The matching layer 7 includes a dielectric substrate 72 and square copper patches 71 covering its surface. In this embodiment, the dielectric substrate 72 is a microwave board, and the uniformly distributed square copper patches 71 constitute the basic matching layer structure. The square copper patches 71 are uniformly distributed on one side of the microwave board at subwavelength intervals. The spacing between the matching layer 7 and the metasurface antenna array 1 where the radiating element 2 is located, as well as the size and spacing of the square copper patches 71, are consistent with the parameters obtained in step 2. A periodic structure model consisting of the matching layer 7 and the equivalent impedance plane of the antenna array radiating elements is used. Analysis of the model yields the initial structural parameters of the matching layer, including the size and spacing of the square copper patches 71, the distance between the matching layer and the antenna array, and the thickness, dielectric constant, and loss of the dielectric substrate 72. A periodic structure is established using three types of radiating elements according to their actual distribution. This periodic structure contains several radiating slots and is rectangular in shape. Within this rectangular area, a matching layer model is built using the initial matching layer parameters. The distance between the matching layer structure and the radiating element array is consistent with the initial data. The four sides of the overall model's periodic structure serve as periodic boundaries. The two ends of this periodic structure perpendicular to the normal of the matching layer 7 or the metasurface antenna array 1 are Floquet port 4 (12) and Floquet port 5 (13). This model allows analysis of the matching result of the matching layer 7 with the phased array antenna array 1. Further optimization of the matching layer parameters is performed on the overall model, and finally, by comparing the presence and absence of a matching layer, the structural parameters of the matching layer are determined. Figure 5 and Figure 6 In the 11~15.5GHz range, the antenna gain increases by at least 1.5dB in the normal direction under matched conditions, and the gain decreases by no more than 4dB relative to the normal gain when scanned to 60°. The relative permittivity of the matching layer is 3.5, and the size of the square copper patch 71 is 4mm, achieving good matching characteristics.

[0048] Furthermore, the dielectric substrate 72 of the matching layer 7 is a double-sided copper-clad board, and square copper patches 71 are processed by PCB etching to form a periodic copper layer pattern. For protection, the surface of the copper layer pattern is gold-plated. This matching layer and the antenna array can be filled and supported by foam.

Claims

1. A design method for the matching layer of a Ku-band metasurface phased array antenna, characterized in that, Includes the following steps: Step 1: Establish a non-full-surface antenna model and extract the impedance parameters of the metasurface phased array antenna surface at different frequencies and under different scanning states; Step 2: Using the impedance parameters as boundary conditions, perform preliminary optimization on the matching layer to obtain the initial parameters of the matching layer structure; Step 3: Based on the actual metasurface phased array antenna periodic structure, verify and optimize the initial parameters of the matching layer structure to obtain the final parameters of the matching layer structure.

2. The design method for the matching layer of the Ku-band metasurface phased array antenna according to claim 1, characterized in that, The non-full-array antenna model is a periodic structure model established based on the distribution of radiating elements. This periodic structure model includes various types of radiating element structures and local feeding structures. The local feeding structure is a traveling wave feeding structure, which is located below and closely attached to the array radiating structure composed of radiating elements. The traveling wave feeding structure has feeding ports at both ends in the energy propagation direction and magnetic boundaries on the two sides parallel to the energy propagation direction. The four sides of the radiating elements in the periodic structure model are periodic boundaries, with the feeding ports as the corresponding wave ports and the Floquet port at the end of the radiation space closely attached to the upper part of the periodic boundary.

3. The design method for the matching layer of the Ku-band metasurface phased array antenna according to claim 2, characterized in that, Adjust the Floquet port reference to the array plane containing the corresponding radiating element, and extract the impedance parameters using the following formula: in and The antenna surface impedances are for TE mode and TM mode, respectively. For free space wave impedance, The scanning angle, Let be the reflection coefficient of the Floquet port during H-plane scanning. Let be the reflection coefficient of the Floquet port during E-plane scanning.

4. The design method for the matching layer of the Ku-band metasurface phased array antenna according to claim 2, characterized in that, In step 2, the periodically distributed regular metal patterns on the dielectric substrate are used as the basic model of the matching layer. Each metal pattern is a radiating element. The matching layer model is established according to the minimum size of the radiating element distribution period. A plane with the same size as the matching layer is established vertically below the matching layer model at a certain distance. The equivalent impedance of the phased array antenna surface is assigned to this plane. The plane and the matching layer model together form the required model. Periodic boundary conditions are assigned to the four sides of the required model, and Floquet ports are assigned to the top and bottom end faces. In this way, the S-parameters of the Floquet ports are initially optimized to obtain the initial parameters of the matching layer structure.

5. The design method for the matching layer of the Ku-band metasurface phased array antenna according to claim 4, characterized in that, The establishment of a matching layer model based on the minimum size of the radiative unit distribution period refers to the inclusion of the minimum repeating unit of the matching layer periodic structure in the matching layer model.

6. The design method for the matching layer of the Ku-band metasurface phased array antenna according to claim 4, characterized in that, The method for initially optimizing the Floquet port S-parameters to obtain the initial parameters of the matching layer structure is as follows: By adjusting different structural parameters of the matching layer and calculating the values ​​of the Floquet port S-parameters at the required frequency and scan angle, the structural parameters of the matching layer are then determined to meet the requirements.

7. The design method for the matching layer of the Ku-band metasurface phased array antenna according to claim 4, characterized in that, In step 3, the array surface model of the actual metasurface phased array antenna is constructed, and the matching layer model initially optimized in step 2 is introduced to obtain an overall model. This overall model is then used for analysis, verification, adjustment, and optimization.

8. The design method for the matching layer of the Ku-band metasurface phased array antenna according to claim 7, characterized in that, The actual metasurface phased array antenna has a periodic structure, which includes various types of radiating element structures, and the distribution of radiating elements is consistent with the distribution of radiating elements in the actual phased array antenna. The matching layer model has a periodic structure and adopts the initial parameters of the matching layer structure.

9. The design method for the matching layer of a Ku-band metasurface phased array antenna according to claim 7 or 8, characterized in that, The overall model is constructed as follows: Take the least common multiple of the periodic structure size of the array surface model and the periodic structure size of the matching layer model to make the two models the same size; The overall model is established by vertically aligning the array model and the matching layer model; the overall model is a cuboid, and the spacing between the array and the matching layer is consistent with the spacing between the matching layer and the plane in step 2. The four sides of the overall model are periodic boundaries, and the top and bottom ends are Floquet ports.

10. The design method for the matching layer of the Ku-band metasurface phased array antenna according to claim 9, characterized in that, The analysis, verification, adjustment, and optimization are implemented as follows: The overall model is calculated and adjusted so that the Floquet port S-parameters meet the requirements in terms of the required frequency and scanning angle. At this point, the structural dimensions of the matching layer are the final parameters of the matching layer structure.

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