High-gain low-RCS metasurface antenna with wave beam deflection function

Abstract

The invention provides a high-gain low-RCS (radar cross section) metasurface antenna with a wave beam deflection function, which belongs to the technical field of electromagnetic metamaterials and comprises an upper-layer metasurface and a lower-layer metasurface, and multifunctional regulation and control on an electromagnetic wave radiation scattering mode are realized by adopting the upper-layer metasurface and the lower-layer metasurface which are different in size. Wherein the upper-layer metasurface is a PCM-FSS scattering-transmitting integrated metasurface, and the lower-layer metasurface is a phase gradient metasurface. When the high-gain low-RCS metasurface antenna works in a radiation mode, the upper-layer metasurface emits spherical electromagnetic waves downwards, and when the spherical waves reach the lower-layer metasurface, the spherical waves are reflected into high-gain directional wave beams with the deflection angle being 34 degrees through phase compensation and penetrate through the upper surface to be radiated to a free space; when working in a scattering mode, the upper and lower layers of metasurfaces can deflect reflected waves of external electromagnetic waves to a non-threat angular domain direction. In the frequency band of 8-18 GHz, the RCS reduction amplitude reaches 10 dB or above, and in-band and out-of-band large-amplitude RCS reduction is achieved while high-gain radiation is kept.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic metamaterials, and in particular relates to a high-gain, low RCS metasurface antenna with a beam deflection function. Background Art

[0002] The continuous progress of modern science and technology has led to the rapid development of military electronic technology. Electromagnetic confrontation has opened up a new battlefield for modern warfare. Whether or not the battlefield electromagnetic waves can be effectively controlled is a key factor affecting the outcome of the war, and stealth technology is an important part of it. Radar Coss Section (RCS) is the most important indicator for evaluating the quality of stealth performance. The definition of RCS is 4 times the ratio of the power density of the target scattered to the receiver within a unit solid angle to the power density of the incident wave at the target, that is, the equivalent scattering area presented when the incident radar wave is irradiated. The key to stealth technology lies in reducing the RCS of the target.

[0003] Antennas are important components for receiving and transmitting signals in communication systems. Their radiation characteristics have always been an important research object in the development of electronic information technology. With the development of radar and stealth technology, antennas, as important scatterers in the system, have also received more attention for their scattering characteristics. However, the increase in antenna gain is often inevitably accompanied by a larger aperture area, which is a huge challenge for the low RCS design of the system.

[0004] There are two main conventional RCS reduction methods. One is the shaping technology, which changes the target's contour and deflects the peak of the radar echo to the non-threatening angle, thereby reducing the probability of the target being captured. The other is to apply radar absorbing materials on the surface of the detected target. Its essence is to suppress the appearance of irregular reflection fields by loading lossy materials, and weaken the amplitude of radar echoes by absorption and consumption to achieve low detectability of the target. However, these two methods will have an adverse effect on the antenna radiation characteristics when applied to the antenna system. Therefore, how to better balance the radiation performance and scattering performance of the antenna system has become a technical difficulty in the field of electromagnetic stealth.

[0005] The emergence of electromagnetic metasurfaces provides a new idea for the design of high-gain, low-RCS antennas. By rationally designing metasurface units, the propagation characteristics of electromagnetic waves, such as amplitude and phase, can be flexibly manipulated, thereby realizing the design of multifunctional devices. However, in the currently reported high-gain, low-RCS antennas, achieving significant RCS reduction inside and outside the band, maintaining efficient improvement of antenna gain within the band, and achieving overall design miniaturization are still three difficult requirements to balance.

[0006] Therefore, how to achieve an RCS reduction of more than 10dB in a wide band while maintaining a low profile and ensuring that the antenna has high gain radiation performance is a key issue that needs to be solved urgently. Summary of the invention

[0007] In order to address the shortcomings and deficiencies of the prior art, a high-gain, low RCS metasurface antenna with a beam deflection function is provided, thereby solving the problem that the existing antenna cannot maintain a low profile while achieving an RCS reduction of more than 10dB in a wide band and ensuring that the antenna has high-gain radiation performance.

[0008] In order to achieve the purpose of the present invention, a high-gain, low-RCS metasurface antenna with a beam deflection function is provided, comprising an upper metasurface and a lower metasurface, wherein the upper metasurface is a PCM-FSS scattering-transmitting integrated metasurface, which has a radiation function, and the lower metasurface is a phase gradient metasurface, which can realize beam deflection; an air layer with a height h of 62.5 mm is provided between the lower surface of the PCM-FSS scattering-transmitting integrated metasurface and the upper surface of the phase gradient metasurface.

[0009] As a further improvement of the above scheme, the PCM-FSS diffuse-transmittance integrated metasurface includes a first intermediate layer dielectric substrate, and the upper and lower surfaces of the first intermediate layer dielectric substrate are respectively bonded with a first upper surface metal and a first lower surface metal; the length×width of the first intermediate layer dielectric substrate is 84mm×84mm, the thickness h1 is 3mm, and F4B material with a dielectric constant of 2.65 is adopted; the first upper surface metal includes a first rectangular metal patch and a polarization conversion unit, and the first rectangular metal patch is located at the geometric center of the upper surface of the first intermediate layer dielectric substrate, The length and width of the first rectangular metal patch are 12mm×12mm, and the four groups of polarization conversion units are distributed on the upper surface of the first intermediate layer dielectric substrate in a mirror-symmetrical form around the first rectangular metal patch; the first lower surface metal includes a second rectangular metal patch and a bandpass frequency selection unit, the length and width of the second rectangular metal patch are 7.2mm×7.2mm, the second rectangular metal patch is located at the geometric center of the lower surface of the first intermediate layer dielectric substrate, and the bandpass frequency selection units are evenly distributed around the second rectangular metal patch on the lower surface of the first intermediate dielectric substrate.

[0010] As a further improvement of the above scheme, the phase gradient metasurface includes a second intermediate layer dielectric substrate, and the upper and lower surfaces of the second intermediate layer dielectric substrate are respectively bonded with a second upper surface metal and a second lower surface metal; the length × width of the second intermediate layer dielectric substrate is 150mm × 150mm, the thickness h2 is 3mm, and F4B material with a dielectric constant of 3 is adopted; the second upper surface metal includes a first phase gradient unit, a second phase gradient unit, a third phase gradient unit and a fourth phase gradient unit, and the first phase gradient unit, the second phase gradient unit, the third phase gradient unit and the fourth phase gradient unit are arranged on the upper surface of the second intermediate layer dielectric substrate in a 2-bit encoding manner.

[0011] As a further improvement of the above solution, the polarization conversion unit is a C-shaped ring, symmetrical along the main diagonal, with a period p1 of 6 mm, an inner diameter r1 of 2.2 mm, a width w of 0.4 mm, and an opening angle α of 225°.

[0012] As a further improvement of the above scheme, the bandpass frequency selection unit is a multi-bend cross-slot type, with a period p2 of 6mm, a first slot branch length L1 of 5.7mm, a metal width w1 at the first bend of 0.6mm, a metal width w2 at the second bend of 0.4mm, a second slot branch length L2 of 2.25mm, a third slot branch length L3 of 1.3mm, and a slot width w3 of 0.4mm.

[0013] As a further improvement of the above scheme, the first phase gradient unit is composed of two metal arcs with an outer diameter r2 of 2.2 mm, an opening η of 42°, a width w4 of 0.5 mm, and a metal connecting rod with a width w5 of 0.4 mm. The inclination angle β of the first phase gradient unit is 45°, and the period p3 is 6 mm.

[0014] As a further improvement of the above scheme, the second phase gradient unit is composed of two metal arcs with an outer diameter r2 of 2.2 mm, an opening η of 105°, a width w4 of 0.5 mm, and a metal connecting rod with a width w5 of 0.4 mm. The inclination angle β of the second phase gradient unit is 45°, and the period p3 is 6 mm.

[0015] As a further improvement of the above solution, the third phase gradient unit and the fourth phase gradient unit are obtained by mirror symmetry of the first phase gradient unit and the second phase gradient unit respectively.

[0016] As a further improvement of the above scheme, there is a reflection phase difference of 180° between the first phase gradient unit and the second phase gradient unit, and the reflection amplitude in the 10-12 GHz frequency band is above 0.95; there is a reflection phase difference of 180° between the third phase gradient unit and the fourth phase gradient unit.

[0017] As a further improvement of the above solution, the first phase gradient unit, the second phase gradient unit, the third phase gradient unit and the fourth phase gradient unit have a phase difference of 90° in sequence.

[0018] The beneficial effects of the present invention are:

[0019] Compared with the prior art, the present invention provides a high-gain, low-RCS metasurface antenna with a beam deflection function, which realizes multifunctional control of the electromagnetic wave radiation scattering mode by adopting upper and lower metasurfaces of different sizes, wherein the upper metasurface is a PCM-FSS scattering-transmitting integrated metasurface, and the lower metasurface is a phase gradient metasurface. When the high-gain, low-RCS metasurface antenna works in the radiation mode, the upper metasurface emits spherical electromagnetic waves downward. When the spherical waves reach the lower metasurface, they are reflected through phase compensation to become a high-gain directional beam with a deflection angle of 34° and radiate through the upper surface to the free space; when working in the scattering mode, both the upper and lower metasurfaces can deflect the reflected waves of external electromagnetic waves to the non-threatening angular domain direction. In the 8-18GHz frequency band, the RCS reduction is more than 10dB, and while maintaining high-gain radiation, a substantial RCS reduction is achieved both within and outside the band. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 It is a side view of the PCM-FSS diffusion-transmission integrated metasurface and the phase gradient metasurface in the present invention;

[0022] Figure 3 Schematic diagram of the upper surface of the PCM-FSS diffusion-transmission integrated super surface in the present invention;

[0023] Figure 4 Schematic diagram of the lower surface of the PCM-FSS diffusion-transmission integrated super surface in the present invention;

[0024] Figure 5 Schematic diagram of the upper surface of the phase gradient metasurface in the present invention;

[0025] Figure 6 is a schematic structural diagram of a polarization conversion unit in the present invention;

[0026] Figure 7 It is a structural schematic diagram of the bandpass frequency selection unit in the present invention;

[0027] Figure 8 is a schematic structural diagram of the first phase gradient unit in the present invention;

[0028] Fig. 9 is a schematic structural diagram of the second phase gradient unit in the present invention;

[0029] Fig.10 is a schematic structural diagram of the third phase gradient unit in the present invention;

[0030] Fig.11 is a schematic structural diagram of the fourth phase gradient unit in the present invention;

[0031] Fig.12 This is a simulation result diagram of the transmission / reflection amplitude of the PCM-FSS diffuse-transmit integrated metasurface in the present invention;

[0032] Fig.13 This is a simulation result diagram of the polarization conversion rate of the PCM-FSS diffuse-transmit integrated metasurface in the present invention;

[0033] Fig.14 Graph showing the reflection phase simulation results of the first to fourth phase gradient units in the present invention;

[0034] Fig.15 is a diagram of the reflection amplitude simulation results of the first to fourth phase gradient units in the present invention;

[0035] Fig.16 The present invention and the reference antenna |S 11 |Simulation results comparison chart;

[0036] Fig.17 A comparison diagram of broadband gain simulation between the present invention and a reference antenna;

[0037] Fig.18 1D far-field pattern of the present invention at 10.3 GHz;

[0038] Fig.19 The figure is a comparison chart of the single-station RCS simulation results of the present invention and PEC.

[0039] Among them, 100-PCM-FSS diffuse-transmitting integrated metasurface; 110-first intermediate layer dielectric substrate; 120-first upper surface metal; 121-first rectangular metal patch; 122-polarization conversion unit; 130-first lower surface metal; 131-second rectangular metal patch; 132-bandpass frequency selection unit; 200-phase gradient metasurface; 201-first phase gradient unit; 202-second phase gradient unit; 203-third phase gradient unit; 204-fourth phase gradient unit; 210-second intermediate layer dielectric substrate; 220-second upper surface metal; 230-second lower surface metal. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings:

[0041] according to Figure 1-Figure 2 As shown, the present invention provides a high-gain, low-RCS metasurface antenna with a beam deflection function, comprising an upper metasurface and a lower metasurface, the upper metasurface being a PCM-FSS scattering-transmitting integrated metasurface 100, which has a radiation function, and the lower metasurface being a phase gradient metasurface 200, which can realize beam deflection; an air layer with a height h of 62.5 mm is provided between the lower surface of the PCM-FSS scattering-transmitting integrated metasurface 100 and the upper surface of the phase gradient metasurface 200.

[0042] Among them, Figure 2 As shown, the PCM-FSS diffuse-transmitting integrated metasurface 100 includes a first intermediate dielectric substrate 110, and the upper and lower surfaces of the first intermediate dielectric substrate 110 are respectively bonded with a first upper surface metal 120 and a first lower surface metal 130; the length×width of the first intermediate dielectric substrate 110 is 84mm×84mm, the thickness h1 is 3mm, and F4B material with a dielectric constant of 2.65 is adopted; the first upper surface metal 120 includes a first rectangular metal patch 121 and a polarization conversion unit 122, the first rectangular metal patch 121 is located at the geometric center of the upper surface of the first intermediate dielectric substrate 110, and the first rectangular metal patch 121 is located at the geometric center of the upper surface of the first intermediate dielectric substrate 110. The length and width of the sheet 121 are 12 mm × 12 mm, and the four groups of polarization conversion units 122 are distributed on the upper surface of the first intermediate layer dielectric substrate 110 in a mirror-symmetrical form around the first rectangular metal patch 121; the first lower surface metal 130 includes a second rectangular metal patch 131 and a bandpass frequency selection unit 132, the length and width of the second rectangular metal patch 131 are 7.2 mm × 7.2 mm, the second rectangular metal patch 131 is located at the geometric center of the lower surface of the first intermediate layer dielectric substrate 110, and the bandpass frequency selection unit 132 is uniformly distributed around the second rectangular metal patch 131 on the lower surface of the first intermediate dielectric substrate 110.

[0043] like Figure 2 As shown, the phase gradient metasurface 200 includes a second intermediate layer dielectric substrate 210, and the upper and lower surfaces of the second intermediate layer dielectric substrate 210 are respectively bonded with a second upper surface metal 220 and a second lower surface metal 230; the length×width of the second intermediate layer dielectric substrate 210 is 150mm×150mm, the thickness h2 is 3mm, and the F4B material with a dielectric constant of 3 is adopted; the second upper surface metal 220 includes a first phase gradient unit 201, a second phase gradient unit 202, a third phase gradient unit 203 and a fourth phase gradient unit 204, and the first phase gradient unit 201, the second phase gradient unit 202, the third phase gradient unit 203 and the fourth phase gradient unit 204 are arranged on the upper surface of the second intermediate layer dielectric substrate 210 according to a 2-bit encoding method, and the first phase gradient unit 201, the second phase gradient unit 202, the third phase gradient unit 203 and the fourth phase gradient unit 204 have a phase difference of 90° in sequence.

[0044] like Figure 6 As shown, the polarization conversion unit 122 is a C-shaped ring, symmetrical along the main diagonal line, with a period p1 of 6 mm, an inner diameter r1 of 2.2 mm, a width w of 0.4 mm, and an opening angle α of 225°.

[0045] like Figure 7 As shown, the bandpass frequency selection unit 132 is a multi-bend cross-slot type, with a period p2 of 6 mm, a first slot branch length L1 of 5.7 mm, a metal width w1 at the first bend of 0.6 mm, a metal width w2 at the second bend of 0.4 mm, a second slot branch length L2 of 2.25 mm, a third slot branch length L3 of 1.3 mm, and a slot width w3 of 0.4 mm.

[0046] like Figure 8 As shown, the first phase gradient unit 201 is a "quasi-I-shaped" pattern, consisting of two metal arcs with an outer diameter r2 of 2.2 mm, an opening η of 42°, a width w4 of 0.5 mm, and a metal connecting rod with a width w5 of 0.4 mm. The inclination angle β of the first phase gradient unit 201 is 45°, and the period p3 is 6 mm.

[0047] like Fig. 9 As shown, the second phase gradient unit 202 is a "quasi-I-shaped" pattern, consisting of two metal arcs with an outer diameter r2 of 2.2 mm, an opening η of 105°, a width w4 of 0.5 mm, and a metal connecting rod with a width w5 of 0.4 mm. The inclination angle β of the second phase gradient unit 202 is 45°, and the period p3 is 6 mm.

[0048] like Figure 10-11As shown, the third phase gradient unit 203 and the fourth phase gradient unit 204 are obtained by mirror symmetry of the first phase gradient unit 201 and the second phase gradient unit 202 respectively; there is a reflection phase difference of 180° between the first phase gradient unit 201 and the second phase gradient unit 202, and the reflection amplitude in the 10-12 GHz frequency band is above 0.95; there is a reflection phase difference of 180° between the third phase gradient unit 203 and the fourth phase gradient unit 204.

[0049] like Fig.12 As shown in the figure, the PCM-FSS diffuse-transmitting metasurface has a high transmittance at 9.7-10.4 GHz, and |Tyy| reaches above 0.7 at 10.3 GHz. In the 13-18 GHz frequency band, it has high cross-polarization reflection and low co-polarization reflection, |Rxy| reaches above 0.95, and |Ryy| remains below 0.25.

[0050] like Fig.13 As shown in the figure, the PCR of the PCM-FSS diffuse-transparent integrated metasurface in the 13-18 GHz frequency band reaches above 0.9. According to the numerical relationship between the RCS reduction amplitude and the PCR, it can be seen that in this frequency band, the PCM-FSS diffuse-transparent integrated metasurface can achieve an RCS reduction effect of more than 10 dB.

[0051] like Fig.14 As shown, in the 8-13 GHz frequency band, the reflection phases of the first phase gradient unit 201 , the second phase gradient unit 202 , the third phase gradient unit 203 and the fourth phase gradient unit 204 differ by 90°, which can be used for 2-bit quantization to form a beam deflection surface.

[0052] like Fig.15 As shown, in the 8-13 GHz frequency band, the reflection amplitude difference between the first phase gradient unit 201 and the third phase gradient unit 203 is within 0.02, and the reflection amplitude difference between the second phase gradient unit 202 and the fourth phase gradient unit 204 is within 0.02. According to the multivariate phase cancellation theory, the phase gradient surface composed of the first phase gradient unit 201, the second phase gradient unit 202, the third phase gradient unit 203 and the fourth phase gradient unit 204 can achieve a good RCS reduction effect in this frequency band. In the 10-13 GHz frequency band, the reflection amplitude difference between the first phase gradient unit 201, the second phase gradient unit 202, the third phase gradient unit 203 and the fourth phase gradient unit 204 is within 0.1. According to the reflection array theory, the beam deflection surface composed of them can achieve good beam focusing and deflection effects.

[0053] like Fig.16As shown, the high-gain low RCS metasurface antenna with beam deflection function provided by the present invention has a high gain and low RCS metasurface antenna in the 9.2-10.7 GHz frequency band. 11 |All below -10dB.

[0054] like Fig.17 As shown, compared with the reference antenna, the high-gain, low-RCS metasurface antenna with beam deflection function provided by the present invention has a gain improvement of more than 10 dB in the 9.7-10.7 GHz frequency band, and its gain reaches 18.8 dBi at 10.3 GHz.

[0055] like Fig.18 As shown, at 10.3 GHz, a high-gain, low-RCS metasurface antenna with a beam deflection function provided by the present invention can radiate a pencil beam with a tilt angle of 34°, a gain of 18.8 dBi, and a 3dB beam width of 18.6°; the cross polarization component is significantly lower than the co-polarization component, indicating that a high-gain, low-RCS metasurface antenna with a beam deflection function provided by the present invention can obtain a relatively pure polarized wave.

[0056] like Fig.19 As shown, compared with PEC, the high-gain, low-RCS metasurface antenna with beam deflection function provided by the present invention has an RCS reduction of more than 10 dB in the 8-18 GHz range, with a maximum reduction of 28.3 dB, and has a good radar stealth effect.

[0057] In summary, the high-gain, low-RCS metasurface antenna with beam deflection function provided by the present invention has good high-gain, low-RCS performance, radiates a directional beam with an inclination angle of 34° of 18.8dBi within 10.3GHz, and reduces the RCS by more than 10dB within 8-18GHz. It has the advantages of small size, low cost, good performance, etc., and has high practicality.

[0058] The above embodiments are not limited to the technical solutions of the embodiments themselves, and the embodiments can be combined with each other to form new embodiments. The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Any modification or equivalent replacement that does not deviate from the spirit and scope of the present invention shall be included in the scope of the technical solutions of the present invention.

Claims

1. A high-gain, low-RCS metasurface antenna with beam deflection function, characterized in that: The invention comprises an upper metasurface and a lower metasurface, wherein the upper metasurface is a PCM-FSS scattering-transmitting integrated metasurface (100) having a radiation function, and the lower metasurface is a phase gradient metasurface (200) capable of realizing beam deflection; an air layer with a height h of 62.5 mm is provided between the lower surface of the PCM-FSS scattering-transmitting integrated metasurface (100) and the upper surface of the phase gradient metasurface (200).

2. The high-gain, low-RCS metasurface antenna with beam deflection function according to claim 1, characterized in that: The PCM-FSS diffuse-transmittance integrated metasurface (100) comprises a first intermediate dielectric substrate (110), wherein the upper and lower surfaces of the first intermediate dielectric substrate (110) are respectively bonded with a first upper surface metal (120) and a first lower surface metal (130); the length×width of the first intermediate dielectric substrate (110) is 84 mm×84 mm, the thickness h1 is 3 mm, and the F4B material with a dielectric constant of 2.65 is used; the first upper surface metal (120) comprises a first rectangular metal patch (121) and a polarization conversion unit (122), wherein the first rectangular metal patch (121) is located at the geometric center of the upper surface of the first intermediate dielectric substrate (110), and the first rectangular metal patch ( The length and width of the first intermediate dielectric substrate (110) are 12 mm × 12 mm, and the four groups of polarization conversion units (122) are respectively distributed on the upper surface of the first intermediate dielectric substrate (110) around the first rectangular metal patch (121) in a mirror-symmetrical form; the first lower surface metal (130) includes a second rectangular metal patch (131) and a bandpass frequency selection unit (132), the length and width of the second rectangular metal patch (131) are 7.2 mm × 7.2 mm, the second rectangular metal patch (131) is located at the geometric center of the lower surface of the first intermediate dielectric substrate (110), and the bandpass frequency selection unit (132) is uniformly distributed on the lower surface of the first intermediate dielectric substrate (110) around the second rectangular metal patch (131).

3. The high-gain, low RCS metasurface antenna with beam deflection function according to claim 2, characterized in that: The phase gradient metasurface (200) comprises a second intermediate layer dielectric substrate (210), wherein the upper and lower surfaces of the second intermediate layer dielectric substrate (210) are respectively bonded with a second upper surface metal (220) and a second lower surface metal (230); the second intermediate layer dielectric substrate (210) has a length×width of 150 mm×150 mm, a thickness h2 of 3 mm, and is made of F4B material with a dielectric constant of 3; the second upper surface metal (220) comprises a first phase gradient unit (201), a second phase gradient unit (202), a third phase gradient unit (203), and a fourth phase gradient unit (204); the first phase gradient unit (201), the second phase gradient unit (202), the third phase gradient unit (203), and the fourth phase gradient unit (204) are arranged on the upper surface of the second intermediate layer dielectric substrate (210) in a 2-bit coding manner.

4. The high-gain, low-RCS metasurface antenna with beam deflection function according to claim 3, characterized in that: The polarization conversion unit (122) is a C-shaped ring, symmetrical along the main diagonal line, with a period p1 of 6 mm, an inner diameter r1 of 2.2 mm, a width w of 0.4 mm, and an opening angle α of 225°.

5. The high-gain, low-RCS metasurface antenna with beam deflection function according to claim 4, characterized in that: The bandpass frequency selection unit (132) is a multi-bend cross-slit type, with a period p2 of 6 mm, a first slot branch length L1 of 5.7 mm, a metal width w1 at the first bend of 0.6 mm, a metal width w2 at the second bend of 0.4 mm, a second slot branch length L2 of 2.25 mm, a third slot branch length L3 of 1.3 mm, and a slot width w3 of 0.4 mm.

6. The high-gain, low RCS metasurface antenna with beam deflection function according to claim 5, characterized in that: The first phase gradient unit (201) is composed of two metal arcs with an outer diameter r2 of 2.2 mm, an opening η of 42°, a width w4 of 0.5 mm, and a metal connecting rod with a width w5 of 0.4 mm. The inclination angle β of the first phase gradient unit (201) is 45°, and the period p3 is 6 mm.

7. The high-gain, low RCS metasurface antenna with beam deflection function according to claim 6, characterized in that: The second phase gradient unit (202) is composed of two metal arcs with an outer diameter r2 of 2.2 mm, an opening η of 105°, a width w4 of 0.5 mm, and a metal connecting rod with a width w5 of 0.4 mm. The inclination angle β of the second phase gradient unit (202) is 45°, and the period p3 is 6 mm.

8. The high-gain, low RCS metasurface antenna with beam deflection function according to claim 7, characterized in that: The third phase gradient unit (203) and the fourth phase gradient unit (204) are respectively obtained by mirror symmetry of the first phase gradient unit (201) and the second phase gradient unit (202).

9. The high-gain, low-RCS metasurface antenna with beam deflection function according to claim 8, characterized in that: There is a reflection phase difference of 180° between the first phase gradient unit (201) and the second phase gradient unit (202), and the reflection amplitude in the 10-12 GHz frequency band is greater than 0.95; there is a reflection phase difference of 180° between the third phase gradient unit (203) and the fourth phase gradient unit (204).

10. The high-gain, low RCS metasurface antenna with beam deflection function according to claim 9, characterized in that: The first phase gradient unit (201), the second phase gradient unit (202), the third phase gradient unit (203) and the fourth phase gradient unit (204) have a phase difference of 90° in sequence.

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