Design method of large-spacing low-sidelobe uniform array

Abstract

The invention discloses a design method of a large-spacing low-sidelobe uniform array, and belongs to the technical field of array antennas. The method comprises the following steps: firstly, designing an initial structure of a movable phase center antenna unit and acquiring far-field data of the antenna unit; then, according to an array antenna design index, constructing an array antenna and obtaining a far-field directional diagram; optimizing the phase center of the array element by using a genetic algorithm to obtain the position distribution of the optimized phase center; finally, the structure of each array element is changed, so that the phase center of each array element is moved to an optimization result; and finally, the design is completed through verification. According to the method, the movable phase center antenna units are used as array elements, and array far-field sidelobes can be reduced without changing the excitation amplitude and phase of each unit in array distribution with uniform spacing.

Description

Technical Field

[0001] The invention belongs to the technical field of array antennas, and in particular relates to a design method for realizing a large-spacing, low-sidelobe uniform array based on a mobile antenna unit phase center. Background Art

[0002] Antennas are widely used in mobile communications, wireless measurement, radar, satellites, navigation and other fields. As an important research field of antenna design, array antennas have developed rapidly due to their ability to obtain specific radiation characteristics.

[0003] The phase center of the antenna unit is the position of a point related to the antenna. If this point is used as the center of the equiphase sphere of the antenna radiation far field, the phase of a given field component on the radiation far field sphere should be approximately constant. By adjusting the phase center of the antenna unit, the far-field radiation pattern can be changed, thereby affecting the radiation performance of the array antenna. In the composition of the array antenna, the unit spacing is a basic parameter. Generally, an array with a unit spacing greater than one wavelength is called a large-spacing array antenna. Compared with a full-array antenna with a half-wavelength spacing, a large-spacing array antenna can achieve the same gain with a smaller number of array elements, which greatly saves the array implementation cost. However, due to the large array element spacing, undesirable grating lobes will appear in the radiation pattern of the array, and relevant technologies need to be used to reduce the grating lobes to improve the array performance. In addition, the sidelobe level of the array antenna is also an important parameter that affects the antenna performance. In practical applications, the sidelobe level is generally required to be as low as possible to improve the directivity and accuracy of the array antenna. In addition, a lower sidelobe level can also suppress the interference of irrelevant signals and improve the signal-to-noise ratio and performance of the system, which is of great significance for production and life applications.

[0004] There are many ways to reduce the sidelobe of array antennas. The most common method is to change the excitation amplitude weights of each unit in the array, such as array synthesis methods such as Taylor distribution or Chebyshev distribution. In addition, the distance between the units in the array can be changed, that is, a non-uniform array is formed to reduce the sidelobe level of the array. With the rapid development of computer technology, many intelligent global optimization algorithms have emerged, such as genetic algorithms (GA) and particle swarm algorithms (PSO). The reduction of array sidelobes can also be achieved by performing random search optimization on the excitation of array units and the unit spacing.

[0005] Although the above methods can effectively reduce the sidelobe level of the array, there are also some problems: changing the excitation of each unit of the array requires additional configuration of T / R components, which will greatly increase the implementation cost of the array; the design, processing and testing of non-uniform arrays are more complicated due to the different spacing between each unit, which increases the difficulty of array implementation.

[0006] In recent years, some foreign scholars have proposed to change the far-field radiation pattern of the array by moving the phase center of each array element, thereby reducing the array sidelobe level. The specific method of moving the phase center of the array element is to design a dual-feed port antenna unit that can work in two modes, and move the phase center by changing the excitation amplitude ratio of the two feeding ports. This method can reduce the far-field sidelobe level of the uniform array, but it requires additional configuration of T / R components to change the excitation amplitude ratio of the two feeding ports of each array element, which increases the implementation cost and is not conducive to large-scale array applications. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a design method for a large-spacing low-sidelobe uniform array, which utilizes a movable phase center antenna unit as an array element and can reduce the far-field sidelobes of the array in a uniformly spaced array distribution without changing the excitation amplitude and phase of each unit.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A design method for a large-spacing low-sidelobe uniform array comprises the following steps:

[0010] Step 1. Design the initial structure of the movable phase center antenna unit;

[0011] Step 2. Obtain far-field data of the movable phase center antenna unit;

[0012] Step 3. Take the movable phase center antenna unit as an array element, determine the number of array elements N and the uniform array element spacing d according to the array antenna design index, and construct an array antenna; obtain the array far-field pattern according to the constructed array antenna and the far-field data of the movable phase center antenna unit; take the sidelobe level of the array antenna as the optimization target, use the genetic algorithm to optimize the phase center of the array element, and obtain the phase center position distribution of each array element;

[0013] Step 4. Change the structure of each array element so that the phase center of each array element moves to the optimization result obtained in step 3;

[0014] Step 5. Perform simulation verification on the array antenna after moving the phase center of the array element to obtain the far-field pattern sidelobe level of the array antenna; if the far-field pattern sidelobe level meets the design specifications, the design is completed; if not, return to step 3 to re-optimize the position distribution of the phase center.

[0015] Preferably, in step 3, the basic parameters of the genetic algorithm are set, including: the population size is set in the range of 200 to 600, the maximum number of iterations is set in the range of 200 to 500, the crossover probability is set in the range of 0.25 to 0.9, and the mutation probability is set in the range of 0.01 to 0.1; the optimization objective function is set to objv = |SLL-SLL0|, where SLL is the array sidelobe level in a certain iteration, and SLL0 is the expected array sidelobe level.

[0016] Preferably, the initial structure of the movable phase center antenna unit comprises: an upper dielectric substrate, a parasitic metal patch on the top of the upper dielectric substrate, a lower dielectric substrate, a metal plate at the bottom of the lower dielectric substrate, and three metal patches arranged in parallel and at equal intervals between the upper dielectric substrate and the lower dielectric substrate; the parasitic metal patch coincides with the center of the upper dielectric substrate; the three metal patches are divided into a left metal patch, a middle metal patch and a right metal patch, a PIN diode is loaded above and below the left metal patch and the right metal patch, and the middle metal patch is connected to the coaxial feeding port;

[0017] By changing the position of the parasitic metal patch and simultaneously changing the on-off state of the PIN diodes loaded on the left metal patch and the right metal patch, that is, changing the structure of the movable phase center antenna unit, the phase center of the antenna unit is changed.

[0018] Preferably, in step 2, when the PIN diode is in a conducting state, the far-field data of the movable phase center antenna unit is acquired.

[0019] Preferably, the upper dielectric substrate and the lower dielectric substrate are square dielectric substrates with the same side lengths; the metal plate is a square metal plate with a side length greater than that of the lower dielectric substrate.

[0020] Preferably, the size of the parasitic metal patch is 11 mm×24 mm;

[0021] The sizes of the left metal patch and the right metal patch are both 2mm×34mm, the size of the middle metal patch is 2mm×30mm, and the distances between the left metal patch and the right metal patch and the middle metal patch are both 10mm; at 1.8mm from the upper and lower edges of the left metal patch and the right metal patch, symmetrical gaps of 1.45mm are left for installing PIN diodes, and each PIN diode has the same model.

[0022] The distance between the coaxial feeding port and the upper edge of the middle metal patch is 12.5 mm, and the interface impedance of the coaxial feeding is 50Ω.

[0023] Preferably, the upper dielectric substrate and the lower dielectric substrate are both Roger s5880 dielectric substrates with a relative dielectric constant of 2.2, and both have a size of 60 mm×60 mm, wherein the thickness of the upper dielectric substrate is 10 mm, and the thickness of the lower dielectric substrate is 6 mm.

[0024] Preferably, the metal plate is a metal conductor copper with a size of 96.78 mm×96.78 mm and a thickness of 0.035 mm.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention proposes a design method for a large-spacing low-sidelobe uniform array, which changes the radiation pattern of the unit by moving the phase center of the antenna unit, thereby reducing the side lobes of the entire array pattern;

[0027] 2. The present invention can achieve the goal of reducing far-field side lobes by only changing the phase center distribution of antenna units in a large-spacing uniform array, without changing the array element spacing and the excitation amplitude and phase of the antenna units, thereby reducing the complexity and implementation cost of the array;

[0028] 3. The present invention moves the phase center by changing the structure of the antenna unit. Compared with the method of foreign scholars moving the phase center by changing the excitation amplitude ratio of the two feeding ports, the present invention does not require additional T / R components, thereby reducing the array implementation cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Flowchart of the design method for achieving sidelobe reduction in a large-spacing uniform array for moving the phase center of antenna elements;

[0030] Figure 2 is a three-dimensional structural schematic diagram of an initial structure of a movable phase center antenna unit in an embodiment of the present invention;

[0031] Figure 3 A three-dimensional structural perspective view of an initial structure of a movable phase center antenna unit in an embodiment of the present invention;

[0032] Figure 4 is a schematic top view of an initial structure of a movable phase center antenna unit in an embodiment of the present invention;

[0033] Figure 5 is a side view schematic diagram of an initial structure of a movable phase center antenna unit in an embodiment of the present invention;

[0034] Figure 6 A schematic diagram of three metal patches and a loaded PIN diode between an upper dielectric substrate and a lower dielectric substrate of an initial structure of a movable phase center antenna unit in an embodiment of the present invention;

[0035] Figure 7 is the S11 parameter of the initial structure of the movable phase center antenna unit in the embodiment of the present invention;

[0036] Figure 8 The far-field E-plane and H-plane two-dimensional radiation patterns of the initial structure of the movable phase center antenna unit in the embodiment of the present invention;

[0037] Fig. 9 2D radiation patterns of the far field E-plane and H-plane when the PIN diodes 154 and 155 of the movable phase center antenna unit in the embodiment of the present invention are in the on state and the PIN diodes 156 and 157 are in the off state;

[0038] Fig.10 The far-field H-plane two-dimensional radiation pattern when the PIN diodes 154 and 155 of the movable phase center antenna unit in the embodiment of the present invention are in the on state, the PIN diodes 156 and 157 are in the off state, and the parasitic metal patch 11 on the top of the upper dielectric substrate is moved to different distances along the positive half axis of the x-axis of the plane rectangular coordinate system xoy;

[0039] Fig.11 It is a top view schematic diagram of a large-spacing uniform array after the phase center of each antenna unit is moved in an embodiment of the present invention;

[0040] Fig.12 The far-field two-dimensional radiation pattern of the large-spacing uniform array is compared with that of the one with the phase center of the antenna unit moved and that of the one without moving in the embodiment of the present invention.

[0041] In the figure: 10, the initial structure of the movable phase center antenna unit, 11, the parasitic metal patch, 12, the upper dielectric substrate, 13, the lower dielectric substrate, 14, the metal plate, 15, the three metal patches, 16, the coaxial feeding port, 151, the left metal patch, 152, the middle metal patch, 153, the right metal patch, 154, the PIN diode loaded above the left metal patch, 155, the PIN diode loaded below the left metal patch, 156, the PIN diode loaded above the right metal patch, 157, the PIN diode loaded below the right metal patch. DETAILED DESCRIPTION

[0042] The technical scheme in the embodiment of the present invention will be further described in detail below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] like Figure 1 As shown, a design method of a large-spacing low-sidelobe uniform array in this embodiment includes the following steps:

[0044] Step 1. Design the initial structure of the movable phase center antenna unit.

[0045] In this embodiment, the designed movable phase center antenna unit operates in the frequency band of 3.03-3.12 GHz, and the initial structure is as follows: Figure 2-Figure 6 As shown, it includes: an upper dielectric substrate, a parasitic metal patch on the top of the upper dielectric substrate, a lower dielectric substrate, a metal plate at the bottom of the lower dielectric substrate, and three metal patches arranged parallel and equidistantly between the upper dielectric substrate and the lower dielectric substrate.

[0046] The upper dielectric substrate and the lower dielectric substrate are both square Rogers 5880 dielectric substrates with a relative dielectric constant of 2.2, and both have a size of 60 mm×60 mm, wherein the thickness of the upper dielectric substrate is 10 mm, and the thickness of the lower dielectric substrate is 6 mm.

[0047] The metal plate at the bottom of the lower dielectric substrate is a metal conductor copper, which constitutes the ground of the antenna, has a size of 96.78 mm×96.78 mm, and a thickness of 0.035 mm.

[0048] The size of the parasitic metal patch is 11 mm×24 mm, and the center thereof coincides with the center of the upper dielectric substrate.

[0049] The three metal patches are divided into a left metal patch, a middle metal patch and a right metal patch, with a spacing of 10 mm; the sizes of the left metal patch and the right metal patch are both 2 mm × 34 mm, and a gap of 1.45 mm in length is symmetrically left 1.8 mm away from the upper edge and the lower edge of the left metal patch and the right metal patch for installing the PIN diode; the size of the middle metal patch is 2 mm × 30 mm, and the feeding point connected to the coaxial feeding port is 12.5 mm from the upper edge of the middle metal patch, and the interface impedance of the coaxial feeding is 50 Ω.

[0050] By changing the position of the parasitic metal patch and simultaneously changing the on-off state of the PIN diodes loaded on the left metal patch and the right metal patch, that is, changing the structure of the movable phase center antenna unit, the phase center of the antenna unit is changed.

[0051] Figure 7 is the S11 parameter of the initial structure of the movable phase center antenna unit. It can be seen from the figure that in the frequency range of 3.03-3.12 GHz, the S11 parameter is less than -10 dB, reflecting the resonant characteristics.

[0052] In order to facilitate the description of the position of the parasitic metal patch and the phase center of the antenna unit, the plane rectangular coordinate system xoy is introduced here, such as Figure 4 As shown, in the initial structure of the movable phase center antenna unit, the center of the parasitic metal patch is located at the origin of the plane rectangular coordinate system xoy.

[0053] Step 2. Set all PIN diodes in the movable phase center antenna unit to a conducting state, and obtain far-field data of the movable phase center antenna unit.

[0054] Figure 8 The far-field E-plane and H-plane two-dimensional radiation patterns of the initial structure of the movable phase center antenna unit. It can be seen from the figure that when working at 3.1GHz, the main lobe beam of the H-plane pattern of the movable phase center antenna unit points to 0 degrees. By processing the far-field data, it can be obtained that at this time, the x-axis component of the phase center of the movable phase center antenna unit in the plane rectangular coordinate system xoy is exactly located at x=0.

[0055] Step 3. Use the movable phase center antenna unit as an array element, determine the number of array elements N and the uniform array element spacing d according to the array antenna design index, and construct an array antenna; in this embodiment, the number of units of the array antenna N = 8, and the uniform array element spacing d = 96.78 mm, which is exactly one wavelength when working at 3.1 GHz, forming a 1×8 large-spacing uniform array; based on the far-field data of the constructed array antenna and the movable phase center antenna unit, obtain the array far-field radiation pattern.

[0056] The phase center of the array element is optimized by using a genetic algorithm to obtain the phase center position distribution of each array element. In this embodiment, the basic parameters of the genetic algorithm are set as follows: the population size is 500, the maximum number of iterations is 300, the crossover probability is 0.7, the mutation probability is 0.05, and the optimization objective function is objv = |SLL-SLL0|, where SLL is the array sidelobe level in a certain iteration, SLL0 is the expected array sidelobe level, and the expected sidelobe level is set to -15dB.

[0057] The steps of genetic algorithm-based optimization include:

[0058] Step 1. Set the number of elements of the array antenna N = 8, the array spacing d = 96.78 mm, and the basic parameters of the genetic algorithm: population size is 500, the maximum number of iterations is 300, the crossover probability is 0.7, and the mutation probability is 0.05;

[0059] Step 2. Read the far-field amplitude and phase pattern of the movable phase center antenna unit;

[0060] Step 3. Write the genetic algorithm objective function according to the expected array sidelobe level to constrain the array sidelobe level. The objective function is: objv = |SLL-SLL0|;

[0061] Step 4. Run the genetic algorithm to obtain a uniform array antenna after the phase center of each antenna unit is moved;

[0062] Step 5. Calculate the far-field pattern and sidelobe level of the array antenna after the phase center of each antenna unit is moved again, and calculate the objective function value, that is, the difference between the array sidelobe level in the current iteration and the expected array sidelobe level;

[0063] Step 7. Repeat steps 5 and 6 until the maximum number of iterations is reached, at which point the optimal solution is obtained, that is, the difference between the iterated array sidelobe level and the expected array sidelobe level is minimized, and the final low sidelobe uniform array antenna is obtained.

[0064] The final position distribution of the phase center of each unit is shown in Table 1.

[0065] Table 1

[0066]

[0067] Here, the position distribution of the phase center only considers the distribution on the x-axis of the plane rectangular coordinate system xoy, and is the offset distance relative to the geometric center of each antenna unit. Each antenna unit establishes a separate plane rectangular coordinate system xoy at the geometric center, where a positive number indicates that the phase center is on the positive half axis of the x-axis on the antenna unit, a negative number indicates that the phase center is on the negative half axis of the x-axis on the antenna unit, and zero indicates that the phase center is at the geometric center of the antenna unit.

[0068] Step 4. Change the structure of each array element so that the phase center of each array element moves to the optimization result obtained in step 3.

[0069] The specific method of changing the structure of the movable phase center antenna unit is as follows: first, the conduction state of the PIN diode is changed, the PIN diodes 154 and 155 are in the conduction state, the PIN diodes 156 and 157 are in the disconnection state, and the position of the parasitic metal patch is kept unchanged; Fig. 9 The far-field E-plane and H-plane two-dimensional radiation patterns of the antenna unit in this state are shown. It can be seen from the figure that when working at 3.1GHz, the main lobe beam of the H-plane pattern of the movable phase center antenna unit in this state no longer points to 0 degrees, but to 5 degrees. By processing the far-field data, it can be obtained that at this time, the phase center of the movable phase center antenna unit is located at x = 6.63mm in the x-axis component of the plane rectangular coordinate system xoy, that is, the position of the phase center has changed.

[0070] Then change the position of the parasitic metal patch. Here, PIN diodes 154 and 155 are still in the on state, and PIN diodes 156 and 157 are in the off state. Move the parasitic metal patch along the positive half axis of the x-axis of the plane rectangular coordinate system xoy, and the moving distances are 0mm, 5mm, 10mm, 15mm and 20mm respectively. Fig.10 The far-field H-plane two-dimensional radiation pattern of the antenna unit at different moving distances is shown. It can be seen from the figure that when working at 3.1GHz, as the moving distance of the parasitic metal patch along the positive half axis of the x-axis continues to increase, the main lobe beam pointing angle of the antenna unit H-plane pattern gradually increases. By processing the far-field data, it can be obtained that at this time, the phase center of the movable phase center antenna unit in the plane rectangular coordinate system xoy is x=8.25mm, x=12.24mm, x=15.82mm, x=17.44mm and x=18.03mm respectively. It can be found that at this time, the phase center of the antenna unit can be gradually changed along the positive half axis of the x-axis.

[0071] Since the structure of the movable phase center antenna unit is symmetrical, if PIN diodes 154 and 155 are in the disconnected state, PIN diodes 156 and 157 are in the turned-on state, and the parasitic metal patch is moved along the negative half-axis of the x-axis of the plane rectangular coordinate system xoy, the phase center of the antenna unit can be gradually changed along the negative half-axis of the x-axis.

[0072] In order to move the phase center of each antenna unit to the optimization result of the genetic algorithm, it is necessary to adjust the structure of each antenna unit, and finally obtain the structure of each movable phase center antenna unit that meets the requirements as shown in Table 2. The moving distance of the upper parasitic metal patch is a positive number, which means it moves toward the positive half axis of the x-axis, and the moving distance is a negative number, which means it moves toward the negative half axis of the x-axis. The moving distance of zero means no movement.

[0073] Table 2

[0074]

[0075] Fig.11 A top-down schematic diagram of a large-spacing uniform array is shown after the phase center of each antenna unit is moved.

[0076] Step 5. Perform simulation verification on the array antenna after moving the phase center of the array element to obtain the sidelobe level of the far-field radiation pattern of the array antenna.

[0077] Fig.12The figure shows the comparison of the far-field two-dimensional radiation pattern of a large-spacing uniform array with and without moving the phase center of the antenna unit. It can be seen from the figure that by moving the phase center distribution of the antenna unit, the sidelobe level of the uniform array is -13.7dB, which is close to the expected sidelobe level of -15dB. Compared with the uniform array without moving the phase center of the antenna unit, the sidelobe is reduced by 5.6dB, which is a significant effect.

[0078] The purpose of the present invention is to optimize the design of an array antenna by moving the phase center of an antenna unit. By moving the phase center of an antenna unit to change the radiation pattern of each antenna unit, the sidelobe reduction of a large-spacing uniform array radiation pattern can be achieved without changing the array element spacing and the excitation amplitude and phase of the antenna unit, thereby reducing the complexity and implementation cost of the array.

[0079] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A design method for a large-spacing low-sidelobe uniform array, characterized in that: The following steps are involved: Step 1. Design the initial structure of the movable phase center antenna unit; Step 2. Obtain far-field data of the movable phase center antenna unit; Step 3. Using the movable phase center antenna unit as an array element, determining the number of array elements N and the uniform array element spacing d according to the array antenna design index, and constructing an array antenna; According to the far-field data of the constructed array antenna and the movable phase center antenna unit, the array far-field pattern is obtained; the sidelobe level of the array antenna is taken as the optimization target, and the phase center of the array element is optimized by using the genetic algorithm to obtain the phase center position distribution of each array element; Step 4. Change the structure of each array element so that the phase center of each array element moves to the optimization result obtained in step 3; Step 5. Perform simulation verification on the array antenna after moving the phase center of the array element to obtain the sidelobe level of the far-field radiation pattern of the array antenna; If the sidelobe level of the far-field pattern meets the design specification, the design is completed. If not, return to step 3 to re-optimize the position distribution of the phase center.

2. A design method for a large-pitch low-sidelobe uniform array as claimed in claim 1, characterized in that: In step 3, the basic parameters of the genetic algorithm are set, including: the population size is set in the range of 200 to 600, the maximum number of iterations is set in the range of 200 to 500, the crossover probability is set in the range of 0.25 to 0.9, and the mutation probability is set in the range of 0.01 to 0.1; the optimization objective function is set to objv = |SLL-SLL0|, where SLL is the array sidelobe level in a certain iteration, and SLL0 is the expected array sidelobe level.

3. The design method of a large-pitch low-sidelobe uniform array as claimed in claim 2, characterized in that: The initial structure of the movable phase center antenna unit includes: an upper dielectric substrate, a parasitic metal patch on the top of the upper dielectric substrate, a lower dielectric substrate, a metal plate at the bottom of the lower dielectric substrate, and three metal patches arranged in parallel and at equal intervals between the upper dielectric substrate and the lower dielectric substrate; the parasitic metal patch coincides with the center of the upper dielectric substrate; the three metal patches are divided into a left metal patch, a middle metal patch and a right metal patch, a PIN diode is loaded above and below the left metal patch and the right metal patch, and the middle metal patch is connected to the coaxial feeding port; By changing the position of the parasitic metal patch, the on-off state of the PIN diode loaded by the left metal patch and the right metal patch is changed at the same time, thereby changing the phase center of the antenna unit.

4. The design method of a large-pitch low-sidelobe uniform array as claimed in claim 3, characterized in that: In step 2, when the PIN diode is in the on state, the far-field data of the movable phase center antenna unit is obtained.

5. The design method of a large-pitch low-sidelobe uniform array as claimed in claim 4, characterized in that: The upper dielectric substrate and the lower dielectric substrate are square dielectric substrates with the same side lengths; the metal plate is a square metal plate, and the side length is greater than the side length of the lower dielectric substrate.

6. A method for designing a large-pitch low-sidelobe uniform array as claimed in claim 5, characterized in that: The size of the parasitic metal patch is 11 mm × 24 mm; The sizes of the left metal patch and the right metal patch are both 2mm×34mm, the size of the middle metal patch is 2mm×30mm, and the distances between the left metal patch and the right metal patch and the middle metal patch are both 10mm; 1.8mm away from the upper edge and the lower edge of the left metal patch and the right metal patch, a gap of 1.45mm in length is symmetrically left for installing PIN diodes, and the PIN diodes are of the same model; The distance between the coaxial feeding port and the upper edge of the middle metal patch is 12.5 mm, and the interface impedance of the coaxial feeding is 50Ω.

7. A method for designing a large-pitch low-sidelobe uniform array as claimed in claim 6, characterized in that: The upper dielectric substrate and the lower dielectric substrate are both Rogers 5880 dielectric substrates with a relative dielectric constant of 2.2, and both have a size of 60 mm×60 mm, wherein the thickness of the upper dielectric substrate is 10 mm, and the thickness of the lower dielectric substrate is 6 mm.

8. The design method of a large-pitch low-sidelobe uniform array as claimed in claim 7, characterized in that: The metal plate is made of metal conductor copper, has a size of 96.78 mm×96.78 mm, and a thickness of 0.035 mm.

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