RCS-reduced circularly polarized metasurface antenna based on C-band satellite communication

Abstract

This invention belongs to the field of electromagnetic metasurface technology, specifically disclosing an RCS-reduced circularly polarized metasurface antenna for C-band satellite communication. It comprises, from top to bottom, a first metasurface layer, a first dielectric layer, a second metasurface layer, a second dielectric layer, a slotted metal plate, a third dielectric layer, and a feed antenna layer. The first metasurface layer consists of four sets of unit structures arranged mirror-image each other in a two-dimensional direction, with two types of square chamfered patches arranged non-contactly in each set. The second metasurface layer also consists of four sets of unit structures arranged mirror-image each other in a two-dimensional direction, with L-shaped resonant rings arranged in an array in each set. The total number of square chamfered patches and L-shaped resonant rings is the same, with an L-shaped resonant ring located below each square chamfered patch. This antenna is suitable for satellite communication, can reduce the radar cross-section in the 4-10.5 GHz range, and has significant application value in electromagnetic stealth technology.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic metamaterials technology and relates to an RCS-reduced circularly polarized metasurface antenna based on C-band satellite communication. Background Technology

[0002] Metasurfaces, as innovative two-dimensional material structures, are composed primarily of subwavelength-scale artificial electromagnetic resonant units, and have attracted considerable attention for their extraordinary potential in the field of electromagnetic wave manipulation. These metasurface antennas, with their low mass density, compact space occupation, high integration compatibility, and great design flexibility, have become a frontier in scientific research. With the rapid development of satellite communication technology, the performance optimization of antenna systems has become one of the key factors driving technological advancement. The C-band (frequency range between 4 GHz and 8 GHz), with its excellent signal propagation characteristics and relatively low environmental interference level, occupies a pivotal position in the field of satellite communication and is widely used in various communication missions. However, with the dramatic increase in the demand for satellite communication, more stringent performance challenges are posed to antenna systems, including but not limited to higher gain, wider bandwidth, stronger directivity, and better anti-interference capabilities. These requirements drive continuous innovation and breakthroughs in antenna design technology.

[0003] Antennas, as core devices for signal transmission and information exchange, play a crucial role in the communications industry. They are widely used in satellites, drones, aircraft, radar, and many other fields. Especially in aircraft, antennas act as their "eyes," collecting critical information by emitting and receiving electromagnetic waves. To prevent accurate radar targeting, stealth technology becomes paramount. This technology requires reducing the radar cross-section (RCS), essentially reducing the electromagnetic energy reflected from the target received by other radars, thereby shortening the detection range of the radar system. By ensuring that the electromagnetic power of the scattered echo is lower than the radar's receiving accuracy, the risk of the aircraft being destroyed by other forces can be effectively mitigated.

[0004] The traditional methods for reducing the radar cross section of an antenna include: (1) Using specific shapes, materials, or structures to reduce the reflection of radar waves by the antenna. For example, designing antennas with special shapes, such as curved, wavy, or tilted surfaces, can change the scattering direction of electromagnetic waves. However, in some cases, in order to reduce the RCS, it may be necessary to sacrifice the performance of the antenna, such as reducing the antenna gain or increasing the beamwidth, which will affect the communication or detection range. Antennas with specific shapes are often complex in structure, increasing manufacturing costs and maintenance difficulty. (2) Radar absorption material (RAM): Special materials are used in the structure of the antenna that can absorb radar waves instead of reflecting them. However, these materials usually have variations in dielectric constant and permeability, so they can only achieve absorption at specific frequencies. In order to achieve better absorption, RAM usually needs a certain thickness, which increases the weight and volume of the structure. The performance of RAM may be affected by the environment, such as humidity and temperature, and high-quality RAM is expensive. (3) Loaded frequency selective surface (FSS): A frequency selective surface is a periodic structure that allows electromagnetic waves to pass through only at specific frequencies, while reflecting or absorbing electromagnetic waves at other frequencies. When using an FSS (Flat Side Scanner) as a radome or floor, the probed wave can be reflected in other directions, thus reducing the antenna's RCS (Radar Cross Section). However, due to the frequency selectivity, only the out-of-band RCS can be reduced. In-band RCS reduction is more difficult than out-of-band RCS reduction. In-band RCS is closely related to the antenna's own radiation performance, requiring a reduction in radar cross section while maintaining antenna performance.

[0005] The traditional RCS reduction methods mentioned above can all reduce the radar cross section of antennas, but they all have some drawbacks. In recent years, the application of two-dimensional electromagnetic metamaterials (electromagnetic metasurfaces) to reduce the radar cross section of antennas has become a popular research direction. The electromagnetic units of electromagnetic metasurfaces offer design flexibility; by artificially adjusting their electromagnetic properties, precise control over the phase and amplitude of reflected waves can be achieved, thereby effectively reducing the RCS. The unit structures of electromagnetic metasurfaces are typically very thin and lightweight, integrating electrical energy with traditional materials or structures, allowing RCS reduction without significantly increasing weight and volume. This is particularly important for weight-sensitive carriers such as aircraft. Electromagnetic metasurfaces can be designed to respond to electromagnetic waves of specific frequencies or bands, achieving significant RCS reduction within the desired frequency band while maintaining normal performance in other bands. Maintenance of electromagnetic metasurfaces is relatively simple; due to their structural stability, they are not easily affected by the environment and are easy to replace after damage. Because of the advantages of metasurfaces, such as low profile, low cost, and flexible electromagnetic properties, they have been extensively explored and researched by scholars in the design of low-RCS antennas. Summary of the Invention

[0006] This invention provides an in-band reduced RCS circularly polarized metasurface antenna for C-band satellite communication. At a center frequency of 6 GHz, it exhibits an impedance bandwidth (IBW) of 74.6% (3.7 GHz - 8.1 GHz) and an axial ratio bandwidth (ARBW) of 29% (5.6 GHz - 7.5 GHz), achieving a maximum gain of 9.2 dBic at 6 GHz. This makes the proposed array antenna suitable for satellite communication. Furthermore, due to the mirror effect of the metasurface structure, reflected waves are weakened, enabling this antenna array to achieve a reduction in radar cross-section in the 4-10.5 GHz band, with a maximum in-band RCS reduction of 26.8 dB. This has significant application value in electromagnetic stealth technology.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: an RCS-reduced circularly polarized metasurface antenna based on C-band satellite communication, comprising, from top to bottom, a first metasurface layer, a first dielectric layer, a second metasurface layer, a second dielectric layer, a slotted metal plate, a third dielectric layer, and a feed antenna layer; wherein the first metasurface layer is composed of four sets of unit structures arranged mirror images of each other in a two-dimensional direction, with two types of square chamfered patches arranged non-contactly in each unit structure; the second metasurface layer is composed of four sets of unit structures arranged mirror images of each other in a two-dimensional direction, with L-shaped resonant rings arranged in an array in each unit structure; the total number of square chamfered patches and L-shaped resonant rings is the same, and an L-shaped resonant ring is provided below each square chamfered patch.

[0008] In some embodiments, the first metasurface layer, the second metasurface layer, the slotted metal plate, and the feed antenna layer are made of copper material with a thickness of 0.03-0.04 mm.

[0009] In some embodiments, both the first dielectric layer and the second dielectric layer are FR-4 dielectric layers with a dielectric constant of 4.3, a loss tangent of 0.025, a thickness of 2.8-3 mm, a length of 71-72 mm, and a width of 71-72 mm.

[0010] In some embodiments, the third dielectric layer is an F4B dielectric layer with a dielectric constant of 2.2, a loss tangent of 0.001, a thickness of 0.7-0.8 mm, a length of 71-72 mm, and a width of 71-72 mm.

[0011] In some embodiments, the square chamfered patch in the unit structure of the first metasurface layer has a side length of 5.1-5.2 mm, and each patch has two chamfered corners in the diagonal direction; the two types of square chamfered patches are specifically a large square chamfered patch with a chamfered corner length projection of 3.0-3.1 mm and a small square chamfered patch with a chamfered corner length projection of 2.1-2.2 mm.

[0012] In some embodiments, after the four sets of unit structures of the first metasurface layer are arranged in a mirror image of each other in the two-dimensional direction, seven layers are set from the center outward. The innermost layer consists of 4 large square chamfered patches, the second layer consists of 8 small square chamfered patches, the third layer consists of 8 small square chamfered patches and 4 large square chamfered patches, the fourth layer consists of 16 large square chamfered patches, the fifth layer consists of 8 small square chamfered patches and 4 large square chamfered patches, the sixth layer consists of 8 small square chamfered patches, and the seventh layer consists of 4 large square chamfered patches.

[0013] In some embodiments, the outer side length and inner side length of the L-shaped resonant ring are 7.4-7.5 mm and 5.2-5.3 mm, respectively.

[0014] In some embodiments, the slotted metal plate consists of four sets of unit structures, each set of unit structures has a slot, and the slots of two adjacent sets of unit structures are perpendicular to each other; the length of the slot is lf=23mm and wf=2.6mm.

[0015] In some embodiments, the feed antenna layer employs a sequential feed network, including four sets of microstrip lines, with adjacent sets of microstrip lines perpendicular to each other, and one end of each of the four sets of microstrip lines is connected to and provided with a side-feed waveguide port.

[0016] This invention also relates to the application of the antenna in satellite communication, circularly polarized signal transmission and / or electromagnetic stealth.

[0017] The present invention has the following beneficial effects:

[0018] This invention designs a novel metasurface structure and applies it to antenna array design. Arranging a 4x4 metasurface on a slot antenna array achieves excellent circularly polarized radiation performance and effectively reduces the RCS within the antenna's operating frequency band. After loading the 4x4 metasurface structure, at a center frequency of 6 GHz, the impedance bandwidth with a reflection coefficient below -10 dB is 3.7 GHz–8.1 GHz (74.6%), the bandwidth with an axial ratio below 3 dB is 5.6 GHz–7.5 GHz (29%), and the maximum gain is 9.2 dBic at 6 GHz. Furthermore, the measured results of the antenna show good consistency with the simulation results, verifying that the proposed array antenna is suitable for satellite communication. In addition, when a plane electromagnetic wave illuminates perpendicularly, the mirror effect of the metasurface structure weakens the reflected wave, resulting in a maximum RCS reduction of 26.8 dB compared to a metal ground plane of the same size. The RCS reduction of more than 6 dB occurs in the 4 GHz–10.5 GHz band.

[0019] The antenna provided by this invention can effectively reduce radar detectability within its operating frequency band, thereby improving the stealth performance of the entire system. Attached Figure Description

[0020] Figure 1 In Figures (a) and (b), the unit structure diagrams of the L-shaped metasurface and the rectangular chamfered metasurface of Example 1 are shown respectively.

[0021] Figure 2 In the middle (a) and (b), respectively, are schematic diagrams of the two overall structures of the electromagnetic metasurface in Example 1: the rectangular chamfered top layer and the L-shaped metasurface.

[0022] Figure 3 (a), (b), and (c) are the back, front, and side views of the overall structure of the RCS-reduced circularly polarized metasurface antenna for C-band satellite communication in Example 1, respectively.

[0023] Figure 4 (a) and (b) are the back and front views of the RCS-reduced circularly polarized metasurface antenna for C-band satellite communication in Example 2, respectively.

[0024] Figure 5 In Figures (a) and (b), S represents the sequentially fed antenna in Example 3, respectively. 11 Simulation diagram of curve and axis ratio curve.

[0025] Figure 6 In Figure (a), the in-band reduced circularly polarized metasurface antenna S for C-band satellite communication in Example 3 is shown. 11 The experimental diagram comparing the curve simulation and actual measurement is shown in (b), which is a simulation diagram of the axial ratio and gain curve of the RCS in-band reduced circularly polarized metasurface antenna for C-band satellite communication.

[0026] Figure 7 In the middle (a) and (b), the E-plane and H-plane of the simulated and measured far-field radiation pattern of the RCS-reduced circularly polarized metasurface antenna for C-band satellite communication in Example 3 at 6 GHz are respectively.

[0027] Figure 8 In Figures (a) and (b), the axial ratio and gain curves of the RCS-band reduced circularly polarized metasurface antenna for C-band satellite communication in Example 3 are shown.

[0028] Figure 9 The figure shows the axial ratio curves of different lf lengths of the RCS-band reduced circularly polarized metasurface antenna for C-band satellite communication in Example 3.

[0029] Figure 10 The image in the middle shows a comparison of the RCS reduction of the antenna in Example 3 under the loading of the metasurface structure and the metal plate.

[0030] Figure 11 In Figures (a) and (b), the three-dimensional scattering patterns of the antenna in Example 3 at 7 GHz are shown for the loaded metasurface structure and the metal plate, respectively. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0032] Example 1

[0033] like Figures 1-3 As shown, the C-band satellite communication RCS-reduced circularly polarized metasurface antenna provided in this embodiment consists of four metal layers and three dielectric layers. Specifically, from top to bottom, it comprises a first metasurface layer (square chamfered metasurface), a first dielectric layer, a second metasurface layer (L-shaped metasurface), a second dielectric layer, a slotted metal plate, a third dielectric layer, and a feed antenna layer. The first metasurface layer is a square chamfered patch metasurface layer, specifically composed of four sets of unit structures arranged mirror images of each other in a two-dimensional direction. In each set of unit structures (4*4), two types of square chamfered patches are arranged non-contactly. The second metasurface layer is an L-shaped resonant ring metasurface layer, also composed of four sets of unit structures arranged mirror images of each other in a two-dimensional direction. In each set of unit structures, the L-shaped resonant rings are arranged in an array (4*4). The total number of square chamfered patches and L-shaped resonant rings is the same, with an L-shaped resonant ring located below each square chamfered patch. The period w of the unit structure is 8.5 mm. Multiple unit structures are periodically arranged closely with a spacing of g=1mm, and the overall structure shown is as follows: Figure 2 As shown in (a) and (b) in the figure.

[0034] In the unit structure of the first metasurface layer, the side length of the square chamfered patch is 5.1-5.2mm, and in this embodiment, l3=5.2mm is preferred. Each patch has two chamfered corners in the diagonal direction, and the diagonal chamfered corners are 45°. Specifically, the two types of square chamfered patches are a large square chamfered patch with a chamfered corner length projection of 3.0-3.1mm (in this embodiment, the chamfered corner length projection is b=3mm) and a small square chamfered patch with a chamfered corner length projection of 2.1-2.2mm (in this embodiment, the chamfered corner length projection is a=2.2mm).

[0035] Preferably, after the four sets of unit structures of the first metasurface layer are arranged in a mirror image of each other in the two-dimensional direction, seven layers are set from the center outward. The innermost layer consists of 4 large square chamfered patches, the second layer consists of 8 small square chamfered patches, the third layer consists of 8 small square chamfered patches and 4 large square chamfered patches, the fourth layer consists of 16 large square chamfered patches, the fifth layer consists of 8 small square chamfered patches and 4 large square chamfered patches, the sixth layer consists of 8 small square chamfered patches, and the seventh layer consists of 4 large square chamfered patches.

[0036] In some embodiments, the outer side length and inner side length of the L-shaped resonant ring are 7.4-7.5 mm and 5.2-5.3 mm, respectively. In this embodiment, the outer side length l1=7.5 mm and the inner side length l2=5.3 mm are preferred.

[0037] Preferably, the first metasurface layer, the second metasurface layer, the slotted metal plate, and the feed antenna layer are made of copper with a thickness of 0.03-0.04 mm; more preferably, ts = 0.035 mm. The first and second dielectric layers are both FR-4 dielectric layers with a dielectric constant of 4.3, a loss tangent of 0.025, and a thickness of 2.8-3 mm, more preferably h1 = h2 = 3 mm. The third dielectric layer is an F4B dielectric layer with a dielectric constant of 2.2, a loss tangent of 0.001, and a thickness of 0.7-0.8 mm, more preferably h3 = 0.8 mm. The length of the first, second, and third dielectric layers is 71-72 mm, and in this embodiment, wsub = 72 mm. The width is also 71-72 mm, and in this embodiment, wsub = 72 mm. The total thickness of the metasurface antenna in this embodiment is 6.94 mm.

[0038] In some embodiments, the slotted metal plate consists of four sets of unit structures, each set of unit structures has a slot, and the slots of two adjacent sets of unit structures are perpendicular to each other; the length of the slot is lf=23mm and wf=2.6mm.

[0039] Preferably, the electromagnetic waves output from the four output ports of the sequentially rotated feed antenna radiate through the gaps between the slotted metal plates and couple onto the metasurface. By modulating these electromagnetic waves using a double-layer metasurface structure, the antenna's radiation performance is further optimized, increasing gain and reducing sidelobe levels.

[0040] In some embodiments, the feed antenna layer employs a sequential feed network, including four sets of microstrip lines, with adjacent sets of microstrip lines perpendicular to each other, and one end of each of the four sets of microstrip lines is connected to and provided with a side-feed waveguide port.

[0041] Figure 3 (a) shows the specific dimensions of the slot coupling layer on the back of the antenna and the sequentially fed microstrip lines. Figure 3 (b) is a front perspective view of the antenna; the side structure is as follows. Figure 3 (c) shows the length and width of the sequentially fed microstrip line as referenced in Table 1.

[0042] Table 1

[0043]

[0044] Example 2

[0045] A 72mm × 72mm experimental sample was fabricated using printed circuit board manufacturing technology. Images of the back and front sides are shown below. Figure 4 As shown in (a) and (b) in the figure. And by Figure 6 A comparison of the experimental and simulation results of the reflection curve data was obtained. Observation clearly shows that the experimental data curves are very similar to the simulation data curves, with the experimental results being better than the simulation results. The simulated antenna has an impedance bandwidth of 3.7GHz-8.1GHz below -10dB and a maximum gain of 9.2dBic. Similarly, the simulated antenna has a 3dB axial ratio bandwidth of 5.6GHz-7.5GHz. The measurement results demonstrate the feasibility of the proposed circularly polarized metasurface antenna design method. Figure 7 Figures (a) and (b) show the E-plane and H-plane of the antenna at 6 GHz after simulation and actual measurement with the metasurface applied. It can be seen that the E-plane and H-plane have good symmetry at this time, and the radiation characteristics in the two principal planes are similar, which can achieve relatively uniform radiation coverage.

[0046] Example 3

[0047] To analyze the impact of metamaterial surface structure on impedance matching, this invention analyzes sequentially fed structures with and without a metasurface (i.e., lacking the first metasurface layer, first dielectric layer, second metasurface layer, and second dielectric layer). Without a metasurface, the reflection coefficient curve of the sequentially fed antenna shows a potential decreasing trend in the 4-8 GHz range, but the impedance bandwidth at -10 dB has three frequency bands: 5.7-6 GHz, 6.4-7.2 GHz, and 7.5-7.9 GHz. Figure 5 As shown in (a). With the metasurface applied, the impedance bandwidth below -10dB can be increased to 3.7GHz-8.1GHz, as shown in (a). Figure 6 As shown in (a). Similarly, sequentially fed antennas have the potential advantage of circular polarization performance, such as... Figure 5 (b) The axial ratio curve shows a decreasing trend after 5 GHz, but does not fall below 3 dB. After loading the metasurface, the 3 dB axial ratio bandwidth can reach 5.6 GHz-7.5 GHz, such as... Figure 6 As shown in the AR curve in (b), it can be seen that the impedance bandwidth and axial ratio bandwidth of the antenna are significantly improved after loading the metasurface.

[0048] Example 4

[0049] To study antenna |S 11 The parameters |≤−10dB and AR≤3dB are varied with the feed line size parameters. Simulation experiments on the metasurface antenna are conducted using the controlled variable method. Figure 8 As shown in (a) and (b) above. Parameter la represents the length of the feeder. Figure 8It can be seen that as la increases in 2 mm increments, simulations using CST software reveal that at la = 28 mm and 32 mm, the IBW and ARBW are 5.4-7.1 GHz and 4.2-6.9 GHz, and 2.7-6.2 GHz and 6.9-7.5 GHz, respectively. For la = 30 mm, the impedance bandwidth is 74.6% (3.7 GHz - 8.1 GHz), and the axial ratio bandwidth is 29% (5.6 GHz - 7.5 GHz), indicating a wider bandwidth. Furthermore, when la = 28 mm and 32 mm, the antenna gain is lower than the 9.2 dBic gain at 6 GHz when la = 30 mm. Considering the effects of impedance bandwidth, axial ratio bandwidth, and gain, the optimal feed line length la is 30 mm.

[0050] Example 5

[0051] The influence of the metal ground plane gap length lf on the reflection coefficient of this antenna model was investigated. With wf = 2.6 mm selected, lf increased from 21 mm to 25 mm in 2 mm increments. Figure 9 As can be seen, the axial ratio curves for all three different parameters show a decreasing trend. To ensure better circular polarization performance, the axial ratio should ideally be below 3dB. The simulated curves only meet this requirement when lf = 23mm. At this point, the axial ratio bandwidth reaches 29% (5.6GHz-7.5GHz). Therefore, the optimal metal floor gap length lf is selected as 23mm.

[0052] Example 6

[0053] The proposed metasurface antenna model has the function of RCS reduction. The simulation results of the monostatic RCS of the metal plate without metasurface and this model are compared. Figure 11 Three-dimensional scattering field diagrams with and without metasurface structures are shown at 4.5 GHz. Figure 10 The reduction in RCS is shown. Under plane electromagnetic wave incidence, the average reduction reaches over 6dB in the 4-10.5GHz frequency range, with reductions of 26.8dB and 26.7dB at 4.5GHz and 7GHz respectively. Ultimately, it can be seen that the antenna achieves the best RCS reduction primarily in the 4-10.5GHz frequency range.

[0054] In summary, this invention proposes an in-band reduced RCS circularly polarized metasurface antenna for C-band satellite communication. This device can be used for C-band satellite communication, exhibits good circular polarization performance, and achieves in-band RCS reduction, reducing radar wave detectability and thus improving its stealth effect.

[0055] The above embodiments describe preferred embodiments of the present invention, but the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other way. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A reduced-spot circularly polarized metasurface antenna with in-band RCS for C-band satellite communication, characterized in that: The system comprises, from top to bottom, a first metasurface layer, a first dielectric layer, a second metasurface layer, a second dielectric layer, a slotted metal plate, a third dielectric layer, and a feed antenna layer. The first metasurface layer consists of four sets of unit structures arranged mirror-image of each other in a two-dimensional direction, with two types of square chamfered patches arranged non-contactly in each set. The second metasurface layer also consists of four sets of unit structures arranged mirror-image of each other in a two-dimensional direction, with L-shaped resonant rings arranged in an array in each set. The total number of square chamfered patches and L-shaped resonant rings is the same, with an L-shaped resonant ring located below each square chamfered patch. The side length of the square chamfered patches in the unit structure of the first metasurface layer is 5.1-5.2 mm. The patch has two chamfers in the diagonal direction; the two types of square chamfer patches are a large square chamfer patch with a chamfer projection length of 3.0-3.1mm and a small square chamfer patch with a chamfer projection length of 2.1-2.2mm; after the four sets of unit structures of the first metasurface layer are arranged in a mirror image of each other in the two-dimensional direction, seven layers are set from the center outward. The innermost layer has 4 large square chamfer patches, the second layer has 8 small square chamfer patches, the third layer has 8 small square chamfer patches and 4 large square chamfer patches, the fourth layer has 16 large square chamfer patches, the fifth layer has 8 small square chamfer patches and 4 large square chamfer patches, the sixth layer has 8 small square chamfer patches, and the seventh layer has 4 large square chamfer patches.

2. The antenna according to claim 1, characterized in that: The first metasurface layer, the second metasurface layer, the slotted metal plate, and the feed antenna layer are made of copper with a thickness of 0.03-0.04 mm.

3. The antenna according to claim 1, characterized in that: Both the first and second dielectric layers are FR-4 dielectric layers with a dielectric constant of 4.3, a loss tangent of 0.025, a thickness of 2.8-3 mm, a length of 71-72 mm, and a width of 71-72 mm.

4. The antenna according to claim 1, characterized in that: The third dielectric layer is an F4B dielectric layer with a dielectric constant of 2.2, a loss tangent of 0.001, a thickness of 0.7-0.8 mm, a length of 71-72 mm, and a width of 71-72 mm.

5. The antenna according to claim 1, characterized in that: The outer and inner side lengths of the L-shaped resonant ring are 7.4-7.5 mm and 5.2-5.3 mm, respectively.

6. The antenna according to claim 1, characterized in that: The slotted metal plate consists of four unit structures, each with a slot. The slots of adjacent unit structures are perpendicular to each other. The length of the slot is lf=23mm and wf=2.6mm.

7. The antenna according to claim 1, characterized in that: The feed antenna layer adopts a sequential feed network, which includes four sets of microstrip lines. The adjacent sets of microstrip lines are perpendicular to each other, and one end of each of the four sets of microstrip lines is connected to and provided with a side-feed waveguide port.

8. The application of the antenna according to any one of claims 1 to 7 in the fields of satellite communication, circularly polarized signal transmission and / or electromagnetic stealth.

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