A low RCS patch antenna array based on a polarization-insensitive hybrid metasurface

Abstract

The invention discloses a low RCS patch antenna array based on a polarization-insensitive hybrid metasurface, comprising a first dielectric layer, a metal backplane layer, a second dielectric layer and a third dielectric layer stacked from bottom to top; a power division feeding network is arranged on the lower surface of the first dielectric layer; the metal backplane layer is seamlessly printed between the first dielectric layer and the second dielectric layer, and a plurality of rectangular metal patches are printed on the upper surface of the second dielectric layer; an air cavity is arranged between the second dielectric layer and the third dielectric layer; a polarization-insensitive hybrid metasurface with a chessboard distribution is printed on the upper surface of the third dielectric layer; the polarization-insensitive hybrid metasurface comprises a metamaterial absorber composed of a metamaterial absorber and a metal backplane layer corresponding to a vertical direction, and an AMC composed of a metamaterial absorber and a metal backplane layer corresponding to a vertical direction, wherein the metamaterial absorber and the AMC have an effective phase difference of 180±37°, satisfy the passive phase cancellation condition, and achieve the effect of reducing RCS.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave antenna design, and mainly relates to a low RCS patch antenna array based on a polarization-insensitive hybrid metasurface. Background Art

[0002] With the rapid development of electronic technology, modern warfare has gradually transformed into high-tech electronic warfare and information technology warfare. The development of highly sensitive radar detection technology has made the survival and penetration capabilities of one's own military equipment threatened by over-the-horizon defense strikes. As the main contributor to the radar cross section of weapon platforms, array antennas are crucial to achieve stealth design while ensuring their radiation performance. Based on this, reducing the radar cross section of the antenna without affecting the radiation performance of the antenna is the key to improving the survivability of the weapon platform.

[0003] Unlike other scatterers, antennas are special scatterers that include radiation. Due to their high gain characteristics, they contribute greatly to the total radar cross-section of the system. The RCS reduction capability of the antenna is related to whether the friendly target can avoid detection and tracking by enemy radar, and plays a vital role in the stealth performance of the system.

[0004] With the advent of electromagnetic metamaterials and metasurfaces and the development of radome frequency selection technology, the use of metasurfaces to reduce or even control the radar cross section of antennas has become a hot topic for researchers. However, most current studies only use a single type of metasurface to achieve the stealth function of the antenna, which is very limited in the bandwidth and degree of RCS reduction, and generally can only achieve antenna stealth under a single polarization. Therefore, the use of hybrid metasurfaces for stealth design of antennas has important research and strategic significance. Summary of the invention

[0005] Purpose of the invention: In view of the problems existing in the above-mentioned background technology, the present invention provides a low RCS patch antenna array based on a polarization-insensitive hybrid metasurface, which aims to reduce the antenna RCS as much as possible while ensuring the normal radiation of the antenna, and ensure that it is insensitive to the polarization mode.

[0006] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A low RCS patch antenna array based on a polarization-insensitive hybrid metasurface comprises a first dielectric layer, a metal backplane layer, a second dielectric layer and a third dielectric layer stacked from bottom to top; a power division feeding network is arranged on the lower surface of the first dielectric layer; the metal backplane layer is seamlessly printed between the first dielectric layer and the second dielectric layer, and a plurality of rectangular metal patches are printed on the upper surface of the second dielectric layer; an air cavity is arranged between the second dielectric layer and the third dielectric layer; and a polarization-insensitive hybrid metasurface with a chessboard distribution is printed on the upper surface of the third dielectric layer.

[0008] Furthermore, the polarization-insensitive hybrid metasurface is distributed in a 2*2 chessboard, including a first metasurface RMA and a second metasurface RM B; the first metasurface RM A and the second metasurface RM B are arranged at intervals along the diagonal of the chessboard, and the metasurface layout along the diagonal direction is the same.

[0009] Furthermore, the RM A and the air cavity and the metal backplane layer corresponding to the vertical direction together constitute a metamaterial absorber, which meets the absorption principle and converts part of the electromagnetic energy into heat energy consumption; the RM B and the air cavity and the metal backplane layer corresponding to the vertical direction together constitute an AMC; the metamaterial absorber and the AMC have an effective phase difference of 180±37°, which meets the passive phase cancellation condition and achieves the reduction of RCS.

[0010] Furthermore, the first metasurface RM A includes two 6*6 first metal patch unit arrays arranged diagonally; the first metal patch unit surface adopts a symmetrical Jerusalem structure, including two cross metal patches with the axis as the center of symmetry, with a size of 6.0mm×0.3mm, and four edge metal patches with a size of 5.0mm×0.3mm are vertically arranged at the four ends of the cross metal patch; the periodic size of the first metal patch unit is 7.5mm×7.5mm; 4 lumped resistors are embedded along the four sides of the cross metal patch, and each resistance value is 70Ω.

[0011] Furthermore, the second metasurface RM B includes two 6*6 second metal patch unit arrays arranged diagonally; each second metal patch unit is a square metal ring, the unit period size is 7.5mm×7.5mm, the side length of each square metal ring is 7.0mm, and the width is 0.1mm; 4 lumped resistors are loaded symmetrically along the center of each side of the square metal ring, and each resistance value is 100Ω.

[0012] Furthermore, the first dielectric layer and the second dielectric layer both use a Rogers 5880 dielectric substrate with a size of 90mm×90mm×0.254mm, a dielectric constant of 2.2, and a loss tangent of 0.0009; the third dielectric layer uses a FR-4 dielectric substrate with a size of 90mm×90mm×0.8mm, a dielectric constant of 4.4, and a loss tangent of 0.02; the air cavity is located between the second dielectric layer and the third dielectric layer, with a height of 4mm; the metal backplane layer has a height of 0.035mm.

[0013] Furthermore, a rectangular metal patch with a size of 4*4 is printed on the upper surface of the second dielectric layer; the rectangular metal patch is powered by a power division feeding network on the lower surface of the first dielectric layer through a coaxial feeding method.

[0014] Furthermore, the size of a single rectangular metal patch is 9.7 mm×7.5 mm, and the patch spacing is 19.6 mm.

[0015] Furthermore, the power division feeding network adopts a one-to-sixteen power division feeding method, and the specific combination method is as follows:

[0016] Every two rectangular metal patches are fed through a first-level one-to-two power divider, and then the upper and lower power dividers are cascaded through a second-level one-to-two power divider. Finally, the power dividers are cascaded in sequence to achieve equal-amplitude and in-phase feeding of the antenna array.

[0017] Furthermore, metal feeding holes with a diameter of 1 mm are provided at positions corresponding to the rectangular metal patches on the first dielectric layer, the metal backplane layer, and the second dielectric layer. Each rectangular metal patch is connected to the power division feeding network through the metal feeding hole and is powered by the power division feeding network.

[0018] Beneficial effects:

[0019] The low RCS patch antenna array based on the polarization-insensitive hybrid metasurface designed by the present invention, when the antenna array is in the radiation state, since the first metasurface RM A and the second metasurface RM B themselves project the radiation wave in the antenna band, the hybrid metasurface is equivalent to a bandpass frequency selection layer for the antenna array, and does not affect the normal radiation performance of the antenna. When the antenna is in the scattering state, the metamaterial absorber and the AMC with an effective reflection phase difference are arranged in a 2×2 chessboard, and the principle of absorption and passive phase cancellation is applied to reduce the dual-polarization RCS of the array antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The overall three-dimensional structure diagram of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface of the present invention and the three-dimensional structure diagram of the metamaterial absorber and the AMC;

[0021] Figure 2 A schematic diagram of the structure of a polarization-insensitive hybrid metasurface on the upper surface of the third dielectric layer of a low RCS patch antenna array based on a polarization-insensitive hybrid metasurface according to the present invention;

[0022] Figure 3 A schematic diagram of a rectangular metal patch structure printed on the upper surface of the second dielectric layer of a low RCS patch antenna array based on a polarization-insensitive hybrid metasurface of the present invention;

[0023] Figure 4 It is a schematic diagram of the structure of the power division feeding network on the lower surface of the first dielectric layer of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface of the present invention;

[0024] Figure 5a is the S-parameter curve of the first metasurface RM A of low RCS patch antenna array based on polarization-insensitive hybrid metasurface;

[0025] Figure 5b is the S-parameter curve of the second metasurface RM B of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface;

[0026] Figure 6a Absorption curve of metamaterial absorber for low RCS patch antenna array based on polarization-insensitive hybrid metasurface

[0027] Figure 6b Comparison of reflection amplitudes of metamaterial absorbers and AMC in low RCS patch antenna arrays based on polarization-insensitive hybrid metasurfaces;

[0028] Figure 6c The reflection phase and phase difference of the metamaterial absorber and AMC in the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface;

[0029] Figures 7a-7d The radiation performance comparison diagram of low RCS patch antenna array based on polarization-insensitive hybrid metasurface; Figure 7a The "S"_"11" comparison curves before and after loading the hybrid metasurface; Figure 7b This is a two-dimensional gain comparison diagram at the resonance point of 12.3GHz; Figure 7c is the three-dimensional gain diagram of the reference antenna at the resonance point of 12.3 GHz; Figure 7d The three-dimensional gain diagram of the antenna loaded with the polarization-insensitive hybrid metasurface at the resonance point of 12.3 GHz.

[0030] Figure 8a Schematic diagram of RCS under co-polarized vertical incidence of low RCS patch antenna array based on polarization-insensitive hybrid metasurface;

[0031] Figure 8bSchematic diagram of RCS under cross-polarization vertical incidence of low RCS patch antenna array based on polarization-insensitive hybrid metasurface;

[0032] Figures 9a-9d is the three-dimensional scattering diagram at the resonant frequency of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface; Figure 9a is the reference antenna under co-polarization, Figure 9b Design antenna for the present invention under co-polarization, Fig.9c is the reference antenna under cross-polarization, Figure 9d Designing antennas for the present invention under cross polarization;

[0033] Fig.10a The co-polarization bistatic RCS comparison curve at the resonant frequency of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface;

[0034] Fig.10b The cross-polarization bistatic RCS comparison curve at the resonant frequency of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface;.

[0035] Description of reference numerals:

[0036] 1-first dielectric layer; 2-metal backplane layer; 3-second dielectric layer; 4-air cavity; 5-third dielectric layer; 6-power division feeding network; 7-rectangular metal patch; 8-first metal patch unit; 9-second metal patch unit. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The low RCS patch antenna array based on the polarization-insensitive hybrid metasurface provided in this embodiment includes an upper layer of polarization-insensitive transmission metasurfaces formed by chessboard layout and a lower layer of 4×4 microstrip array antennas with a metal backplane. The specific structure is as follows: Figure 1 As shown, it includes a first dielectric layer 1, a metal back plate layer 2, a second dielectric layer 3 and a third dielectric layer 5 stacked from bottom to top. An air cavity 4 is provided between the second dielectric layer 3 and the third dielectric layer 5, and the height is 4 mm.

[0039] In this embodiment, the first dielectric layer 1 and the second dielectric layer 3 both use a Rogers 5880 dielectric substrate with a size of 90mm×90mm×0.254mm, a dielectric constant of 2.2, and a loss tangent of 0.0009; the third dielectric layer 5 uses a FR-4 dielectric substrate with a size of 90mm×90mm×0.8mm, a dielectric constant of 4.4, and a loss tangent of 0.02; the height of the metal backplane layer 2 is 0.035mm.

[0040] The lower surface of the first dielectric layer 1 is provided with a power division feeding network 6; the metal backplane layer 2 is seamlessly printed between the first dielectric layer 1 and the second dielectric layer 3, and the upper surface of the second dielectric layer 3 is printed with a plurality of rectangular metal patches 7, as shown in FIG. Figure 3-4 shown.

[0041] The upper surface of the second dielectric layer is printed with rectangular metal patches 7 with a size of 4*4; the size of a single rectangular metal patch is 9.7mm×7.5mm, and the patch spacing is 19.6mm. The rectangular metal patches 7 are powered by the power division feeding network 6 on the lower surface of the first dielectric layer through coaxial feeding.

[0042] The power division feeding network 6 adopts a one-to-sixteen power division feeding method, and the specific combination method is as follows: every two rectangular metal patches are fed through a first-level one-to-two power divider, and then the upper and lower power dividers are cascaded through a second-level one-to-two power divider, and finally the power dividers are cascaded in sequence to achieve equal amplitude and in-phase feeding of the antenna array.

[0043] In actual operation, metal feeding holes with a diameter of 1 mm are provided at positions corresponding to the rectangular metal patches on the first dielectric layer, the metal backplane layer, and the second dielectric layer. Each rectangular metal patch is connected to the power division feeding network through the metal feeding hole and is powered by the power division feeding network.

[0044] A polarization-insensitive hybrid metasurface with a chessboard distribution is printed on the upper surface of the third dielectric layer.

[0045] The specific structure of the polarization-insensitive hybrid metasurface is as follows: Figure 1-2 As shown, it is distributed in a 2*2 chessboard, including a first supersurface RM A and a second supersurface RM B; the first supersurface RM A and the second supersurface RM B are arranged at intervals along the diagonal of the chessboard, and the supersurface layout along the diagonal direction is the same.

[0046] The first metasurface RM A includes two 6*6 first metal patch unit arrays arranged diagonally; the first metal patch unit surface adopts a symmetrical Jerusalem structure, including two cross metal patches with the axis as the symmetry center, with a size of 6.0mm×0.3mm, and four edge metal patches with a size of 5.0mm×0.3mm are vertically arranged at the four ends of the cross metal patch; the periodic size of the first metal patch unit is 7.5mm×7.5mm; 4 lumped resistors are embedded along the four sides of the cross metal patch, and each resistance value is 70Ω.

[0047] The second metasurface RM B includes two 6*6 second metal patch unit arrays arranged diagonally; each second metal patch unit is a square metal ring with a unit period size of 7.5mm×7.5mm, a side length of 7.0mm and a width of 0.1mm; four lumped resistors are loaded symmetrically along the center of each side of the square metal ring, and each resistance value is 100Ω.

[0048] The RM A, the air cavity corresponding to the vertical direction, and the metal backplane layer together constitute a metamaterial absorber, which meets the absorption principle and converts part of the electromagnetic energy into heat energy consumption; the RM B, the air cavity corresponding to the vertical direction, and the metal backplane layer together constitute an AMC; the metamaterial absorber and the AMC have an effective phase difference of 180±37°, which meets the passive phase cancellation condition and reduces the RCS.

[0049] The hybrid metasurface units provided in this embodiment are simulated and calculated respectively by using the commercial software HFSS to verify the performance of the antenna array provided by the present invention.

[0050] like Figure 5a-5b As shown, since the designed metasurface units are all symmetrical structures, they are polarization-insensitive. Figure 5a is the S parameter curve of the first metasurface RM A, the transmission coefficient S of RM A in the range of 10.5–14.0 GHz 21 Greater than -3dB, able to transmit the antenna's radiation wave; reflection coefficient S within the antenna's operating frequency band 11 Close to -10dB. Figure 5b is the S parameter curve of the second metasurface RM B, the transmission coefficient S in the range of 10.3–20.0 GHz 21 Transmission coefficient S greater than -3dB within 11.7–20.0GHz 21 Greater than -2dB. Within the working bandwidth of the antenna, the transmission phases of the two metasurface units are close and remain in phase, which can well ensure that the radiation characteristics of the antenna do not change.

[0051] Figure 6a-6cis the simulation characteristic curve of the metamaterial absorber and AMC unit composed of the first metasurface RM A and the second metasurface RM B, Figure 6a It can be seen that the absorption rate of the absorber in the frequency range of 4.6-10.9 GHz is higher than 90%, which meets the requirements of antenna stealth in engineering. Figure 6b It can be seen that due to its absorbing effect in the low frequency band, the reflection coefficient amplitude of the absorber unit in the range of 4.0-11.6GHz is less than 0.5, and the reflection amplitude in the range of 11.2-13.4GHz is in the range of 0.4-0.8; while the AMC composed of RMB is also loaded with lumped resistance, and there is a certain absorption loss. At the same time, the reflection amplitude of AMC in the range of 4.5-17.2GHz remains almost unchanged, both in the range of 0.65-0.8. Figure 6c It can be seen that the reflection phase difference between the two metasurface units is between 180°±37° in the range of 9.9–15.5 GHz, which meets the conditions for passive phase cancellation. Arranging them in a checkerboard pattern can be used to reduce the backward RCS of the array antenna.

[0052] Figures 7a-7d The figure is a comparison of the radiation performance of low RCS patch antenna arrays based on polarization-insensitive hybrid metasurfaces. Specifically, Figure 7a Shown is S 11 Comparing the curves, the resonant frequency of the designed antenna is consistent with that of the reference antenna, and it still resonates at 12.3 GHz. At the same time, in the 12.2 GHz–12.4 GHz frequency band, the S 11 Both are less than -10dB, and the impedance bandwidth is basically the same; the reflection coefficient of the designed stealth antenna at the resonance point of 12.3GHz reaches -14.9dB, which meets the needs of engineering applications. Figure 7b Shown is a two-dimensional radiation pattern comparison curve of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface and the reference antenna at the resonant frequency of 12.3 GHz. The radiation pattern of the designed antenna at the resonant frequency is basically consistent with that of the reference antenna, and the maximum gain of the main lobe reaches 16.0 dB, which is 4.2 dB lower than the 20.2 dB of the reference antenna, while the radiation pattern remains basically unchanged; this is because at the resonant frequency, the transmission coefficients of RM A and RM B are both around -3 dB, and part of the radiation energy is reflected and thus absorbed and canceled to other angular domains, while the transmission characteristics of RM A and RM B provide conditions for the normal radiation of the antenna. Figure 7c and Figure 7d Shown are the three-dimensional gain radiation patterns of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface and the reference antenna at 12.3 GHz. The main lobe gain of the designed antenna does not change basically. It can be considered that loading the hybrid metasurface can still ensure the normal radiation of the antenna.

[0053] Figure 8a-8b The single-station RCS comparison curves of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface and the reference antenna under vertical incidence of electromagnetic waves with different polarizations. The data in the figure are all simulated when the antenna is connected to a matching load. The broadband single-station RCS of the designed antenna under co-polarization and cross-polarization is reduced. This is because the first metasurface and the second metasurface loaded by the antenna are both polarization-insensitive structures. For vertically incident co-polarized waves, such as Figure 8a As shown in the figure, the RCS of the designed antenna is reduced in the 4.0–20.0 GHz band compared with the reference antenna. The single-station RCS reduction value is greater than 10 dB in the 10.2-15.0 GHz band compared with the reference antenna, and the relative bandwidth reaches 38.1%. The single-station RCS reduction value at the resonant frequency of 12.3 GHz is 11.2 dB. At the same time, the single-station RCS reduction of the designed array antenna at 11.6 and 12.6 GHz reaches the maximum values ​​of 25.2 and 25.8 dB, respectively. For vertically incident cross-polarized waves, such as Figure 8b As shown in the figure, compared with the reference antenna, the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface has a slightly higher single-station RCS at 8.2 GHz, while the RCS in the rest of the frequency bands from 4.0 to 20.0 GHz is reduced. The designed antenna achieves a single-station RCS reduction of more than 10 dB in the range of 10.4 to 15.0 GHz, and the relative bandwidth reaches 36.2%. At the same time, the single-station RCS reduction at the resonant frequency of 12.3 GHz reaches a maximum value of 30.7 dB. This is because the reflection coefficient amplitudes of the metamaterial absorber and AMC in this frequency band are both less than 1, and the phase difference of 180°±37° is satisfied, so the RCS reduction effect is improved. At the same time, in the 4.6–10.9 GHz frequency band, the absorption rate of the metamaterial absorber unit composed of RMB reaches 90% or more. Figure 8a-8b It can be seen that in the 4.0–10.0 GHz band, except for 8.2 GHz, the dual-polarization RCS reduction values ​​are all higher than 5 dB. Therefore, loading the hybrid metasurface can simultaneously reduce the in-band RCS of the antenna under dual polarization in the broadband range. Although the gain of the designed antenna is 4 dB lower than that of the reference antenna, it is worthwhile compared to the stealth effect it brings, and the gain of the antenna can be compensated by other compensation methods.

[0054] like Figures 9a-9d As shown in the figure, in order to verify the RCS absorption and cancellation effect of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface under dual polarization, the three-dimensional scattering diagrams at the resonant frequency of 12.3GHz under the vertical incidence of the co-polarized and cross-polarized waves of the array antenna are given respectively. According to the different scale colors in the figure, it can be intuitively seen that the main scattering peak energy of the antenna is suppressed and transferred to other angular domains. Therefore, it can be verified that the designed antenna has an in-band dual-polarization stealth effect.

[0055] like Figure 10a-10b As shown, in order to more intuitively see the RCS reduction effect of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface under dual polarization, the comparison curves of the bistatic RCS of the designed array antenna and the reference antenna at the resonant frequency under vertical incidence of co-polarization and cross-polarization waves are given respectively as a function of angle theta. Under the irradiation of the antenna co-polarization wave and cross-polarization wave, the scattering main peak energy of the bistatic RCS of the designed antenna is reduced. At the resonant frequency, the reflection amplitudes of the absorber and the AMC are close to 0.5, and the reflection phase difference is 186°. At this time, the RCS reduction is the effect of the superposition of absorption and cancellation. As shown Fig.10a As shown in , for the case of vertical incidence of co-polarized waves on the antenna, within the angular domain of ±12.6°, the scattered energy is dispersed to other angular domains; similarly, under the incidence of cross-polarized waves, as shown in Fig.10b As shown in the figure, the scattered energy at 0° is suppressed and transferred to ±16.0°. Therefore, the dual-polarization backward RCS of the low RCS patch antenna array based on the polarization-insensitive hybrid metasurface is effectively reduced.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low RCS patch antenna array based on a polarization-insensitive hybrid metasurface, characterized in that: It comprises a first dielectric layer, a metal backplane layer, a second dielectric layer and a third dielectric layer stacked from bottom to top; a power division feeding network is arranged on the lower surface of the first dielectric layer; the metal backplane layer is seamlessly printed between the first dielectric layer and the second dielectric layer, a plurality of rectangular metal patches arranged in an array are printed on the upper surface of the second dielectric layer, and the rectangular metal patches are powered by the power division feeding network on the lower surface of the first dielectric layer through a coaxial feeding method; an air cavity is arranged between the second dielectric layer and the third dielectric layer; a polarization-insensitive hybrid metasurface with a chessboard distribution is printed on the upper surface of the third dielectric layer, and a plurality of the rectangular metal patches are arranged under each chessboard grid; The polarization-insensitive hybrid metasurface is distributed in a 2*2 chessboard, including a first metasurface RM A and a second metasurface RM B; the first metasurface RM A and the second metasurface RM B are arranged at intervals along the diagonal of the chessboard, and the metasurface layout along the diagonal direction is the same; The RM A, the air cavity corresponding to the vertical direction, and the metal backplane layer together constitute a metamaterial absorber, which meets the absorption principle and converts part of the electromagnetic energy into heat energy consumption; the RM B, the air cavity corresponding to the vertical direction, and the metal backplane layer together constitute an AMC; the metamaterial absorber and the AMC have an effective phase difference of 180±37°, which meets the passive phase cancellation condition and reduces the RCS.

2. A low RCS patch antenna array based on a polarization-insensitive hybrid metasurface according to claim 1, characterized in that: The first metasurface RM A includes two 6*6 first metal patch unit arrays arranged diagonally; the surface of the first metal patch unit adopts a symmetrical Jerusalem structure, including two cross metal patches with an axis as the center of symmetry, with a size of 6.0mm×0.3mm, and four edge metal patches with a size of 5.0mm×0.3mm are vertically arranged at the four ends of the cross metal patch; the periodic size of the first metal patch unit is 7.5mm×7.5mm; 4 lumped resistors are embedded along the four sides of the cross metal patch, and each resistance value is 70Ω.

3. The low RCS patch antenna array based on a polarization-insensitive hybrid metasurface according to claim 1, characterized in that: The second metasurface RM B includes two 6*6 second metal patch unit arrays arranged diagonally; each second metal patch unit is a square metal ring with a unit period size of 7.5mm×7.5mm, a side length of 7.0mm and a width of 0.1mm; four lumped resistors are loaded symmetrically along the center of each side of the square metal ring, and each resistance value is 100Ω.

4. The low RCS patch antenna array based on a polarization-insensitive hybrid metasurface according to claim 1, characterized in that: The first dielectric layer and the second dielectric layer both use Rogers 5880 dielectric substrates with dimensions of 90mm×90mm×0.254mm, a dielectric constant of 2.2, and a loss tangent of 0.0009; the third dielectric layer uses an FR-4 dielectric substrate with dimensions of 90mm×90mm×0.8mm, a dielectric constant of 4.4, and a loss tangent of 0.02; the air cavity is located between the second dielectric layer and the third dielectric layer, with a height of 4mm; the metal backplane layer has a height of 0.035mm.

5. The low RCS patch antenna array based on a polarization-insensitive hybrid metasurface according to claim 1, characterized in that: A rectangular metal patch with a size of 4*4 is printed on the upper surface of the second dielectric layer.

6. The low RCS patch antenna array based on a polarization-insensitive hybrid metasurface according to claim 5, characterized in that: The size of a single rectangular metal patch is 9.7mm×7.5mm, and the patch spacing is 19.6mm.

7. The low RCS patch antenna array based on a polarization-insensitive hybrid metasurface according to claim 5, characterized in that: The power division feeding network adopts a one-to-sixteen power division feeding method, and the specific combination method is as follows: Every two rectangular metal patches are fed through a first-level one-to-two power divider, and then the upper and lower power dividers are cascaded through a second-level one-to-two power divider. Finally, the power dividers are cascaded in sequence to achieve equal-amplitude and in-phase feeding of the antenna array.

8. The low RCS patch antenna array based on a polarization-insensitive hybrid metasurface according to claim 7, characterized in that: Metal feeding holes with a diameter of 1 mm are provided at positions corresponding to the rectangular metal patches on the first dielectric layer, the metal backplane layer and the second dielectric layer. Each rectangular metal patch is connected to the power division feeding network through the metal feeding hole and is powered by the power division feeding network.

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