Low rcs f-p resonant cavity antenna based on lossy metasurface and amc structure

Abstract

The application provides a low-RCS F-P resonant cavity antenna based on a lossy metasurface and an AMC structure, which comprises an absorbing partial reflection surface structure located at an upper portion and a feed antenna structure located at a lower portion; the absorbing partial reflection surface structure comprises a lossy metasurface layer, a metal patch common ground layer and a metal patch AMC1 layer, which are spaced apart by first and second dielectric substrate layers; the feed antenna structure comprises an antenna patch layer, a metal ground plate layer, a coaxial structure and a third dielectric substrate layer, the antenna patch layer and the metal ground plate layer are oppositely arranged on the third dielectric substrate layer, and the coaxial structure is connected between the antenna patch layer and the metal ground plate layer. The application adopts a method of analyzing the wave absorption and reflection performance of the two ports of the PRS structure unit, simplifies the process of integrated design of the low-RCS, high-directivity and high-gain F-P antenna, effectively reduces the overall profile of the antenna, and is more easily integrated with other radio frequency devices.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antennas, and particularly relates to a low-RCS F-P resonant cavity antenna based on a lossy metasurface and an AMC structure. BACKGROUND

[0002] An antenna is an important component of a radar, communication, navigation and other electronic systems for receiving and transmitting electromagnetic waves, and its performance directly affects the efficiency and combat capability of military electronic systems. It is crucial to reduce the radar scattering cross section as much as possible under the premise of not affecting the performance of the antenna to improve the survivability and penetration capability of the combat system. Due to the influence of the antenna performance, the general military antenna has low design freedom, and it is not easy to reduce the radar echo by optimizing the shape; due to the introduction of loss components, the loading of the wave-absorbing material will inevitably affect the ability of the antenna to radiate / receive electromagnetic waves; and the loading of the stealth radome cannot realize the reduction of the in-band RCS, and cannot realize radar stealth in the working frequency band of the antenna. Therefore, balancing the radiation and scattering characteristics in the working frequency band of the antenna is the most important for the design of a low-RCS antenna. In addition, due to the space limitation of military equipment and the high stealth requirement, low-profile design and the improvement of the reduction amount are also crucial for a low-RCS antenna.

[0003] In 1956, G.V.Trentini, an American scientist, innovatively expanded the Fabry-Perot resonant cavity theory to the field of antennas for the first time, took a waveguide horn as a feed, placed a layer of partially reflective surface composed of a metal mesh on the top of the waveguide horn, and made it form an F-P resonant cavity with the antenna floor, so that the electromagnetic wave was significantly improved in the main radiation direction after multiple reflections.

[0004] Due to the characteristics of easy integration and miniaturization of F-P antenna and various feeding methods, there are many studies on low RCS F-P resonant cavity antennas. In 2017, Lei Zhang et al. proposed a low RCS F-P resonant antenna based on diffuse scattering structure. Four partial reflection units with a reflection phase of 270° are designed to achieve diffuse reflection through a certain arrangement, realizing the bistatic RCS reduction of the antenna. However, the reflection phase of the scattering unit changes greatly with frequency, and the RCS reduction bandwidth is narrow, only 40%. In 2021, Weiliang Yu et al. proposed a low RCS F-P resonant antenna loaded with lumped resistors. By loading an absorbing / transmission frequency selective surface above the feed antenna, the out-of-band RCS reduction is achieved. However, due to the low reflection amplitude of the in-band PRS, the peak gain of the antenna is only 11.77dBi. In 2022, You-Feng Cheng et al. proposed a low RCS F-P resonant antenna based on spatial wave path difference. By constructing a spatial wave path difference with a half-area PRS, the phase difference between the electromagnetic waves reflected directly by the resonant cavity lower reflector and the PRS is about 180°, realizing phase cancellation and reducing the RCS of the F-P antenna. However, due to the reduction of the PRS area, the feed radiation electromagnetic wave cannot be effectively reflected, and the peak gain of the antenna is also low. Moreover, under the condition of determining the antenna profile, the spatial wave path difference is greatly affected by the frequency, and the RCS reduction peak of the antenna is low, only 20dB. SUMMARY

[0005] In order to solve the above problems existing in the prior art, the present application provides a low RCS F-P resonant cavity antenna based on lossy metasurface and AMC structure. The technical problems to be solved by the present application are solved by the following technical scheme:

[0006] A low RCS F-P resonant cavity antenna based on lossy metasurface and AMC structure comprises an absorbing partial reflection surface structure 1 located at the upper part and a feed antenna structure 2 located at the lower part.

[0007] The absorbing partial reflection surface structure 1 comprises a lossy metasurface layer 11, a metal patch common ground layer 12, a metal patch AMC1 layer 13, a first dielectric substrate layer 14 and a second dielectric substrate layer 15. The first dielectric substrate layer 14 is arranged between the lossy metasurface layer 11 and the metal patch common ground layer 12, and the second dielectric substrate layer 15 is arranged between the metal patch common ground layer 12 and the metal patch AMC1 layer 13.

[0008] The feed antenna structure 2 comprises an antenna patch layer 21, a metal floor layer 22, a coaxial structure 23 and a third dielectric substrate layer 24, the antenna patch layer 21 and the metal floor layer 22 are arranged on the third dielectric substrate layer 24 and are oppositely arranged, and the coaxial structure 23 is connected between the antenna patch layer 21 and the metal floor layer 22.

[0009] Advantages:

[0010] Compared with the prior art, the present application has the following advantages:

[0011] 1. The F-P resonant cavity antenna form is adopted, the lower feed antenna structure serves as the feed and the lower reflecting surface of the resonant cavity, the upper absorbing PRS layer serves as the upper reflecting surface of the resonant cavity, the periodic resistive patches on the surface of the graphene realize low RCS of the antenna, and the AMC patch structure around the PRS layer and the feed antenna is used to construct the phases of the upper and lower reflecting surfaces in the F-P antenna to realize low profile design of the antenna.

[0012] 2. The microstrip antenna simplifies the design of the feed antenna, the absorbing PRS layer is used to qualitatively analyze the influence of the absorbing PRS layer on the antenna radiation performance, including directivity, radiation efficiency and gain, the overall F-P antenna design is simplified, the absorbing and reflecting performance of the two ports of the PRS unit is reasonably adjusted to simplify the synchronous realization of RCS reduction and high gain of the PRS structure in the F-P antenna design, the proposed antenna can realize RCS reduction within 6-30GHz, and the relative bandwidth reaches 133%.

[0013] 3. When the PRS unit is optimized and designed, frequency offset is adopted to make the resonant frequency of the PRS slightly higher than the working frequency of the antenna, the low absorption and strong reflection of the PRS layer to the bottom radiation antenna are further realized, the radiation efficiency, high directivity and high gain of the overall F-P antenna structure are improved, and the peak gain of the antenna can reach 15dBi.

[0014] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A structure schematic diagram of a low RCS F-P resonant cavity antenna based on lossy metasurface and AMC structure is provided for the embodiments of the present application.

[0016] Figure 2 A schematic diagram of a periodic unit of a partially reflective surface structure is provided for the present application.

[0017] Figure 3 A structure schematic diagram of an antenna patch layer in example 1 is provided for the present application.

[0018] Figure 4This is a schematic diagram of the antenna patch layer in Example 2 provided by the present invention;

[0019] Figures 5 to 14 This is a schematic diagram of the simulation results provided by the present invention. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0021] The technical effects of the present invention will be illustrated below with examples.

[0022] The design concept of this invention is to reduce the broadband RCS of the antenna by using a lossy metasurface, to adjust the reflection phase of the upper and lower reflective surfaces of the FP resonant cavity using an AMC structure to reduce the cavity profile thickness, and to achieve broadband RCS reduction, low profile, and high gain of the FP antenna by using absorption qualitative analysis and resonant frequency shift.

[0023] refer to Figure 1 The present invention provides a low RCS FP resonant cavity antenna based on a lossy metasurface and an AMC structure, comprising: an absorptive partial reflective surface structure 1 located at the upper part and a feed antenna structure 2 located at the lower part;

[0024] The absorptive partial reflective surface structure 1 includes a lossy metasurface layer 11, a metal patch ground layer 12, a metal patch AMC1 layer 13, a first dielectric substrate layer 14, and a second dielectric substrate layer 15; the first dielectric substrate layer 14 is disposed between the lossy metasurface layer 11 and the metal patch ground layer 12, and the second dielectric substrate layer 15 is disposed between the metal patch ground layer 12 and the metal patch AMC1 layer 13.

[0025] The feed antenna structure 2 includes an antenna patch layer 21, a metal ground plane layer 22, a coaxial structure 23, and a third dielectric substrate layer 24. The antenna patch layer 21 and the metal ground plane layer 22 are both disposed on the third dielectric substrate layer 24 and are disposed opposite to each other. The coaxial structure 23 is connected between the antenna patch layer 21 and the metal ground plane layer 22.

[0026] refer to Figure 1 The lossy metasurface layer 11, the metal patch common ground layer 12, and the metal patch AMC1 layer 13 are composed of multiple units with the same period, and the period size of each unit ranges from 0.245λ. t ≤p1≤0.256λ t , λ t =c / f t , where λ t It is the antenna's operating center frequency f t The corresponding wavelength, c is the speed of light in a vacuum, f t It is the center frequency of the antenna's operation.

[0027] Reference Figure 2 Each unit of the lossy metasurface layer 11 is composed of a square thin film resistor 111; each unit of the metal patch ground layer 12 is composed of a first square metal patch 121; and each unit of the metal patch AMC1 layer 13 is composed of a second square metal patch 131.

[0028] The square thin film resistor 111 is a graphene resistor film, the sheet resistance value range of which is 30 Ohm / sq~100 Ohm / sq, and the length a1 value range of which is 0.147λ t ≤a1≤0.168λ t The length a2 value range of the first square metal patch 121 is 0.241λ t ≤a2≤0.253λ t The length a3 value range of the second square metal patch 131 is 0.140λ t ≤a3≤0.182λ t .

[0029] Reference Figure 3 The antenna patch layer 21 is composed of a rectangular metal radiation patch 211 and a metal patch AMC2 structure 212 laid around the metal radiation patch 211; the length l value range of the metal radiation patch 211 is 0.280λ t ≤l≤0.297λ t The width w value range of the metal radiation patch 211 is 0.228λ t ≤w≤0.238λ t The metal patch AMC2 structure 212 is composed of periodically arranged third square metal patches, the length a4 value range of which is 0.161λ t ≤a4≤0.165λ t The interval distance g value range between the third square metal patches is 0.019λ t ≤g≤0.021λ t .

[0030] The length p value range of the metal ground plate layer 22 is 2.450λ t ≤p≤2.842λ t .

[0031] Reference Figure 3 The feeding center of the coaxial structure 23 is located at the geometric center of the metal radiation patch 211 along the y-axis and is offset by a distance y1, the value range of the offset distance y1 being 0.046λ t ≤y1≤0.067λ t The coaxial structure 23 adopts an inner conductor with a radius r i= 0.3 mm, outer conductor radius r o = 1.05 mm coaxial probe structure.

[0032] The first medium substrate layer 14 of the present application adopts a medium with a thickness of h2=2.5 mm and a dielectric constant of 2.65; the second medium substrate layer 15 adopts a medium with a thickness of h3=2.5 mm and a dielectric constant of 2.65; and the third medium substrate layer 24 adopts a medium with a thickness of h1=2.0 mm and a dielectric constant of 2.65.

[0033] Example 1

[0034] Referring to Figure 1 , the embodiment includes an upper absorptive partially reflective surface (PRS) structure 1 and a lower feed antenna structure 2, and the air cavity thickness between the structure 1 and the structure 2 is t=4.8 mm. The absorptive partially reflective surface structure 1 is composed of a graphene resistive patch layer 11, a metal patch ground layer 12, a metal patch AMC structure layer 13, and medium substrate layers 14 and 15 for separating the three layers from each other, and the medium substrate is an F4b plate with a relative dielectric constant of 2.65 and a loss tangent of 0.0009. The feed antenna structure 2 is composed of an antenna patch layer 21, a metal ground plate layer 22, a coaxial structure 23, and a medium substrate layer 24, and the metal radiation patch 211 is connected to the metal ground plate layer 22 through the coaxial structure 23 to form a patch antenna as a feed of the antenna, and the size of the metal ground plate layer 22 is p=70 mm, and the thickness of the third medium plate layer 24 is h1=2 mm. The air cavity between the structure 1 and the structure 2 forms an F-P resonant cavity, and the electromagnetic waves are reflected in the cavity to improve the gain of the bottom patch antenna.

[0035] Referring to Figure 2 , the unit period of the PRS structure 1 is p1=7 mm, the graphene resistive patch layer 11 is printed with a square thin film resistor 111 with a unit size of a1=4.5 mm and a square resistance of 30 Ω / sq; the metal patch ground layer 12 is printed with a first square metal patch 121 with a unit size of a2=6.9 mm and a material of lossy metal copper; and the metal patch AMC1 structure layer 13 is printed with a second square metal patch 131 with a unit size of a3=5.2 mm and a material of lossy metal copper. The thickness between the graphene resistive patch layer 11 and the metal patch ground layer 12 is h2=2.5 mm, and the thickness between the metal patch ground layer 12 and the metal patch AMC1 structure layer is h3=2.5 mm. The square thin film resistor 111 can convert the incident electromagnetic wave energy into heat energy, thereby achieving RCS reduction. The size of the second square metal patch 131 affects the reflection performance of the metal patch AMC1 layer 13, and by adjusting the unit size, the F-P antenna resonant cavity thickness can be reduced.

[0036] Referring to Figure 3 , the antenna patch layer 21 is printed with a metal radiation patch 211 with a size of w=6.5 mm, l=8 mm and a material of metal lossy copper; the feed point of the coaxial structure 23 is located at a distance y1=1.9 mm from the geometric center of the metal radiation patch 211, and the inner and outer conductor radii of the coaxial structure are r i =0.3 mm and r o =1.05 mm, respectively.

[0037] In the present application, the wave-absorbing layer 11 of the partially reflective surface structure 1 can convert the incident electromagnetic wave into heat energy, realizing wideband RCS reduction, and the AMC layer 12 can realize low absorption and strong reflection of the electromagnetic wave excited by the bottom feed patch antenna 2, and the electromagnetic wave is continuously reflected and co-directionally superimposed in the cavity formed by the structure 1 and the structure 2, finally improving the gain and directivity of the F-P antenna.

[0038] Example 2

[0039] In this embodiment, the PRS structure 1 remains unchanged, and an AMC2 metal patch 212 is additionally provided around the metal radiation patch 211 of the antenna patch layer 21, and in addition, the following parameters are adjusted in this embodiment: the PRS layer 1 structure unit period is adjusted to p1=7.3 mm, the sizes of the first square metal patch 121 and the second square metal patch 131 are adjusted to a2=7.2 mm and a3=4 mm. The thickness between the PRS structure 1 and the patch antenna structure 2 is t=2.7 mm. The size of the metal radiation patch 211 is adjusted to w=6.8 mm and l=8.5 mm, the size of the metal ground plane layer 22 is adjusted to p=81.2 mm, and the feed point position of the coaxial structure 23 is adjusted to y1=1.3 mm, and the inner and outer radii of the coaxial structure remain unchanged.

[0040] Referring to Figure 4 , the size of the AMC2 patch structure 212 added to the antenna patch layer 21 is a4=4.7 mm, and the gap size is g=0.55 mm.

[0041] The technical effects of the present example are verified and described below through simulation and experiment.

[0042] 1. Simulation conditions:

[0043] The wave-absorbing and reflecting performance of the two ports of the PRS structure unit of the present application, the reflection coefficient, gain, directivity of the F-P antenna loaded with the PRS structure, and the single station RCS reduction performance are simulated by using the commercial simulation software HFSS_19.0, wherein the upper and lower surfaces of the PRS structure unit correspond to the 1 port and the 2 port during simulation, respectively.

[0044] 2. Simulation content and results:

[0045] Simulation 1, for example 1 of the present application, the reflection phase and amplitude of 2-port in PRS structure unit and the wave absorption rate of two ports are simulated under the period boundary condition. As shown in Figure 5 Fig. (a) in the middle, the zero phase reflection frequency point of 2-port in PRS structure unit is 10.4GHz, the frequency range of reflection phase in-90°~90° is 8.6~12.4GHz, the relative bandwidth is 36.2%, and the reflection amplitude in the frequency band changes in the range of-1.8~-0.2dB. As shown in Figure 5 Fig. (b) in the middle, the wave absorption rate of 1, 2-port in PRS structure unit when electromagnetic wave is incident from 1, 2-port is respectively: 1-port incident, 13.2GHz and 28GHz respectively reach the wave absorption rate peak value of 78% and 82%, 2-port incident, the wave absorption rate peak value is only 5%. The high wave absorption rate of 1-port makes the absorption type PRS can realize RCS reduction in wide frequency band, and the low wave absorption rate of 2-port makes the absorption type PRS weak to the electromagnetic wave absorption of bottom microstrip antenna radiation, which ensures the high gain of F-P antenna.

[0046] Simulation 2, for example 1 of the present application, the reflection coefficient of F-P antenna loaded with PRS is simulated. From Figure 6 It can be seen that after loading PRS layer, the reflection coefficient is less than-10dB in the range of 10.1~10.9GHz, which has good impedance matching in the frequency band.

[0047] Simulation 3, for example 1 of the present application, the efficiency and peak gain of F-P antenna loaded with PRS are simulated. As shown in Figure 7 PRS structure loading makes the maximum gain of the antenna reach 14.2dBi.

[0048] Simulation 4, for example 1 of the present application, the radiation pattern of F-P antenna loaded with PRS is simulated. Figure 8 The radiation patterns of the antenna before and after loading PRS at 10.3GHz are given, it can be seen that the main radiation direction of the antenna keeps in the normal direction of the antenna floor, after loading the absorption type PRS, the directivity of the antenna is improved significantly, the main radiation direction is improved by 10dB, the 3dB wave number width of E plane and H plane is 25.1°, and the side lobe average is less than 13.5dB.

[0049] Simulation 5, for example 1 of the present application, the single station RCS reduction performance of F-P antenna loaded with PRS is simulated. As shown in Figure 9 The antenna realizes RCS reduction in the wide band of 8GHz~30GHz, and the RCS reduction performance is the strongest at 12GHz and 29GHz, which respectively reaches 14.8dB and 15.2dB.

[0050] Simulation 6 simulates the reflection phase and amplitude of the two ports of the PRS structural unit and the antenna patch layer 21, as well as the absorption rate of the two ports of the PRS layer 1 structural unit when electromagnetic waves are incident on them respectively, for Example 2 of the present invention. Figure 10 As shown in Figures (a) and (b), at 10.5 GHz, the reflection phase at the 2-port of the PRS structural unit is 92°, the reflection amplitude is -0.68 dB, and the reflection phase of the antenna patch layer 21 is 3°. The reduction in the sum of the reflection phases of the upper and lower reflective surfaces in the resonant cavity effectively reduces the thickness of the FP resonant cavity. Figure 11 It can be seen that the absorption rate of port 1 in the PRS structure unit is greater than 60% in the range of 11 to 27.5 GHz, and the absorption rate reaches a peak of 91% at 14 GHz. The absorption rate of port 2 reaches a peak of 3.7% at 11.5 GHz. The absorption resonant frequency is slightly higher than the antenna operating frequency, which further reduces the absorption rate at the antenna operating frequency to ensure the high gain of the FP antenna.

[0051] Simulation 7 simulates the reflection coefficient of the FP antenna after applying PRS, based on Example 2 of this invention. Figure 12 This demonstrates that the present invention achieves impedance matching in the range of 10.3 to 10.7 GHz.

[0052] Simulation 8 simulates the overall efficiency and peak gain achievable by the FP antenna after PRS loading, based on Example 2 of the present invention. Figure 13 As shown, the antenna maintains a radiation efficiency of 60% to 70% within the operating frequency band, and can achieve a peak gain of 15 dBi at 10.5 GHz.

[0053] Simulation 9 simulates the single-site RCS reduction performance of the FP antenna after applying PRS, based on Example 2 of this invention. Figure 14 As shown, due to the loading of the absorbing PRS, the overall structure achieves ultra-wideband RCS reduction in the range of 6 to 30 GHz, with a relative bandwidth of 133% and a peak reduction of 35 dB. Moreover, the RCS reduction in the operating frequency band is greater than 10 dB.

[0054] The simulation results above demonstrate that the low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure of this invention simultaneously achieves the three functions of low RCS, high gain, and low profile through the absorptive partial reflective surface structure and the bottom feed antenna structure, which simplifies the design of FP antennas and improves the shortcomings of existing technologies.

[0055] It is to be noted that the terms "first", "second", and the like in the description do not necessarily connote any actual physical or chronological order, quantity, or importance. Rather, they are merely used to distinguish one element from another. In the description, "a plurality" means two or more, unless expressly specified otherwise.

[0056] Although the present application has been described in connection with various embodiments thereof, it will be understood that other modifications will be apparent to those of ordinary skill in the art and can be made without departing from the spirit and scope of the application, which are indicated by the following claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality.

[0057] The above description is further to specific preferred embodiments of the present application and is not to be construed in any way as limiting the present application. It is to be understood by those skilled in the art that a number of further modifications and / or improvements can be made hereto without departing from the scope of the present application.

Claims

1. A low RCS FP resonant cavity antenna based on a lossy metasurface and an AMC structure, characterized in that, include: The upper part has an absorptive partial reflective surface structure (1) and the lower part has a feed antenna structure (2); The absorption-type partial reflective surface structure (1) includes a lossy metasurface layer (11), a metal patch ground layer (12), a metal patch AMC1 layer (13), a first dielectric substrate layer (14), and a second dielectric substrate layer (15); the first dielectric substrate layer (14) is disposed between the lossy metasurface layer (11) and the metal patch ground layer (12), and the second dielectric substrate layer (15) is disposed between the metal patch ground layer (12) and the metal patch AMC1 layer (13); The feed antenna structure (2) includes an antenna patch layer (21), a metal ground plane layer (22), a coaxial structure (23), and a third dielectric substrate layer (24). The antenna patch layer (21) and the metal ground plane layer (22) are both disposed on the third dielectric substrate layer (24) and are disposed opposite to each other. The coaxial structure (23) is connected between the antenna patch layer (21) and the metal ground plane layer (22).

2. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 1, characterized in that, The lossy metasurface layer (11), the metal patch ground layer (12), and the metal patch AMC1 layer (13) are composed of a plurality of units with the same period, and the period size of each unit ranges from 0.245λ to 0.256λ t . t . t . t wherein λ t is the wavelength corresponding to the center frequency f t of the antenna, c is the speed of light in vacuum, and f t is the center frequency of the antenna.

3. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 2, characterized in that, Each unit of the lossy metasurface layer (11) is composed of a square thin film resistor (111); each unit of the metal patch ground layer (12) is composed of a first square metal patch (121); each unit of the metal patch AMC1 layer (13) is composed of a second square metal patch (131).

4. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 3, characterized in that, The square thin-film resistor (111) is a graphene resistive film with a sheet resistance ranging from 30 Ohm / sq to 100 Ohm / sq, and its side length a1 ranging from 0.147λ. t ≤a1≤0.168λ t .

5. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 3, characterized in that, The side length a2 of the first square metal patch (121) ranges from 0.241λ. t ≤a2≤0.253λ t .

6. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 3, characterized in that, The side length a3 of the second square metal patch (131) ranges from 0.140λ. t ≤a3≤0.182λ t .

7. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 1, characterized in that: The antenna patch layer (21) consists of a rectangular metal radiating patch (211) and a metal patch AMC2 structure (212) surrounding it; The length l of the metal radiating patch (211) ranges from 0.280λ. t ≤l≤0.297λ t The width w ranges from 0.228λ. t ≤w≤0.238λ t The metal patch AMC2 structure (212) is composed of periodically arranged third-dimensional metal patches, and the side length a4 of the third-dimensional metal patch ranges from 0.161λ. t ≤a4≤0.165λ t The spacing g between the three-dimensional metal patches ranges from 0.019λ. t ≤g≤0.021λ t .

8. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 1, characterized in that, The side length p of the metal floor layer (22) ranges from 2.450λ. t ≤p≤2.842λ t .

9. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 7, characterized in that, The feed center of the coaxial structure (23) is located at a position offset by y1 along the y-axis from the geometric center of the metal radiating patch (211), and the offset distance y1 ranges from 0.046λ. t ≤y1≤0.067λ t ; The coaxial structure (23) uses an inner conductor radius r i =0.3mm, outer conductor radius r o =1.05mm coaxial probe structure.

10. The low RCS FP resonant cavity antenna based on a lossy metasurface and AMC structure according to claim 1, characterized in that, The first dielectric substrate layer (14) is made of a dielectric material with a thickness of h2 = 2.5 mm and a dielectric constant of 2.65; The second dielectric substrate layer (15) is made of a dielectric with a thickness of h3 = 2.5 mm and a dielectric constant of 2.65; The third dielectric substrate layer (24) is made of a dielectric with a thickness of h1 = 2.0 mm and a dielectric constant of 2.65.

Images