Programmable metasurface simultaneously compatible with electromagnetic stealth and dynamic radiation

Abstract

The invention discloses a programmable metasurface compatible with electromagnetic stealth and dynamic radiation at the same time, the programmable metasurface is composed of M * N programmable units, M and N are positive integers, all the programmable units have identical geometric structures, but the orientation of the units is 0 degree or 90 degrees, when the metasurface is detected by arbitrarily polarized plane electromagnetic waves emitted by a far-field radar, the metasurface can randomly scatter incoming wave electromagnetic energy to all directions of a space, so that the radar scattering sectional area of the metasurface is very small, complete-polarization electromagnetic stealth is realized, and under the irradiation of spherical electromagnetic waves emitted by a near-field feed source, the near-field electromagnetic energy can be reflected by the metasurface. By controlling the state of the diode loaded on each programmable unit, the metasurface can regulate and control the beam direction of reflected electromagnetic waves in real time, and dynamic electromagnetic radiation is achieved. Compared with an existing programmable metasurface, under the condition of the same electric size, the programmable metasurface compatible with electromagnetic stealth and dynamic radiation has the advantages that the radar cross section area is lower, and meanwhile, the capability of fast beam scanning is still kept; the method has important application prospects in the fields of satellite communication, radar detection, electronic countermeasure, beam forming and the like.

Description

Technical Field

[0001] This invention belongs to the fields of antenna technology and novel artificial electromagnetic metamaterials, and particularly relates to a programmable metasurface that is compatible with both electromagnetic stealth and dynamic radiation. Background Technology

[0002] Metasurfaces, as two-dimensional metamaterials, are typically composed of periodically arranged subwavelength units. They can flexibly manipulate electromagnetic waves and possess advantages such as low profile and ease of fabrication, making them a research hotspot in scientific and engineering fields in recent years. By flexibly designing the structure and arrangement of programmable units, the phase, amplitude, polarization, and even frequency of electromagnetic waves can be controlled, enabling functions such as anomalous refraction, electromagnetic cloaking, and holographic imaging. However, once a passive metasurface is designed, its ability to manipulate electromagnetic waves is fixed, making it unable to meet diverse practical needs.

[0003] To overcome this limitation, in 2014, Professor Cui Tiejun's research group first proposed and designed a reflective digital programmable metasurface. Combined with a field-programmable gate array (FPGA), the switching state of diodes applied to the programmable units is controlled by a bias voltage, allowing the phase response of the programmable units to rapidly switch between "0" and "1" states. By encoding the phase state of each unit on this programmable metasurface in real time, real-time control and switching of arbitrary electromagnetic functions can be achieved. However, existing programmable metasurfaces have a large radar cross-section when performing dynamic beamforming, and lack electromagnetic stealth capabilities. No researchers have yet proposed a programmable metasurface that simultaneously possesses broadband electromagnetic stealth and dynamic beamforming capabilities. Its applications are wide-ranging, including improving the stealth capabilities of weapons and equipment in the defense field and reducing electromagnetic interference in electronic devices in the civilian field. Summary of the Invention

[0004] Technical Problem Solved: This invention discloses a programmable metasurface that simultaneously achieves electromagnetic stealth and dynamic radiation. When detected by arbitrary polarization planar electromagnetic waves emitted by a far-field radar, the metasurface can randomly scatter the incoming electromagnetic energy into various directions in space, resulting in a very small radar cross-section and achieving fully polarized electromagnetic stealth. Under illumination by spherical electromagnetic waves emitted from a near-field feed source, by controlling the state of the diodes loaded on each programmable unit, the metasurface can adjust the beam direction of the reflected electromagnetic waves in real time, achieving dynamic electromagnetic radiation. Technical solution

[0005] A programmable metasurface that is compatible with both electromagnetic stealth and dynamic radiation is provided. The programmable metasurface consists of M×N programmable units, where M and N are positive integers. M is the number of units along the X-axis of the metasurface, and N is the number of units along the Y-axis of the metasurface. All programmable units have the same geometry, but the orientation of the programmable units is either 0° or 90°.

[0006] When the programmable metasurface is detected by arbitrarily polarized planar electromagnetic waves emitted by a far-field radar, the metasurface can randomly scatter the electromagnetic energy of the incoming wave into various directions in space, making its radar cross-section very small and achieving fully polarized electromagnetic stealth.

[0007] Under the illumination of spherical electromagnetic waves emitted by a near-field feed source, the programmable metasurface controls the state of the diodes loaded on each programmable unit through a field-programmable gate array (FPGA). The metasurface can adjust the beam direction of the reflected electromagnetic waves in real time to achieve dynamic electromagnetic radiation.

[0008] Compared with existing programmable metasurfaces, the programmable metasurface has a lower radar cross section under the same electrical dimensions, and can simultaneously achieve fully polarized electromagnetic stealth and dynamic electromagnetic radiation.

[0009] Furthermore, for arbitrary polarized plane electromagnetic waves emitted by far-field radar, the programmable metasurface will generate relative phase delays of 0° and 180° for its circular polarization component by the programmable units pointing at 0° and 90°, respectively. The two electromagnetic waves with a phase difference of 180° will coherently cancel each other out in the positive reflection direction. Since the programmable units pointing at 0° and 90° are randomly arranged, the detection electromagnetic waves emitted by far-field radar are randomly scattered by the programmable metasurface into various directions in space, which greatly reduces the echo electromagnetic energy received by far-field radar. That is, the radar cross-section of the programmable metasurface detected by far-field radar is very small, realizing fully polarized electromagnetic stealth.

[0010] Furthermore, compared with a smooth metal plane of the same size, the programmable metasurface has a radar cross-section reduction of more than 10 dB, a center operating frequency of 10 GHz, and a relative bandwidth of more than 20%.

[0011] Furthermore, each programmable unit is stacked from top to bottom in the following order: a first metal layer, a first dielectric layer, a second metal layer, a prepreg layer, a third metal layer, a second dielectric layer, and a fourth metal layer. A grounding first metal blind via passes through the first dielectric layer, and left-handed and right-handed first metal blind vias pass through the first dielectric layer, the second metal layer, and the prepreg layer. Left-handed and right-handed second metal blind vias pass through the second dielectric layer. A left-handed diode is soldered to the left side of the first metal layer, and a right-handed diode is soldered to the right side of the first metal layer.

[0012] The third metal layer of the programmable unit includes a left-handed fan-shaped metal patch, a right-handed fan-shaped metal patch, a left-handed first feed line, and a right-handed first feed line; the left-handed first metal feed line is connected to the left side of the first metal layer through a left-handed first metal blind hole, and the right-handed first metal feed line is connected to the right side of the first metal layer through a right-handed first metal blind hole.

[0013] The fourth metal layer of the programmable unit includes a left-handed second metal feed line and a right-handed second metal feed line; the left-handed second metal feed line is connected to the left-handed first metal feed line through a left-handed second metal blind via, and the right-handed second metal feed line is connected to the right-handed first metal feed line through a right-handed second metal blind via; a left-handed bias voltage is applied to the left-handed second metal feed line to control the state of the left-handed diode, and a right-handed bias voltage is applied to the right-handed second metal feed line to control the state of the right-handed diode.

[0014] Furthermore, the programmable unit has a period of 7.5 mm, a first dielectric layer thickness of 3 mm, a prepreg layer thickness of 0.2 mm, and a second dielectric layer thickness of 1 mm. The dielectric constants of the first and second dielectric layers are both 2.65, and the tangent loss angle is 0.001. The dielectric constant of the prepreg layer is 3.52, and the tangent loss angle is 0.004.

[0015] Furthermore, the first metal layer of the programmable unit covers the first dielectric layer and has a square open ring structure. The middle part of the first metal layer is connected to the grounding first metal blind hole. The left part of the first metal layer is welded with a left-handed diode, the right part of the first metal layer is welded with a right-handed diode, the left part of the first metal layer is connected to the left-handed first metal blind hole, and the right part of the first metal layer is connected to the right-handed first metal blind hole.

[0016] Furthermore, each programmable unit of the programmable metasurface is loaded with a left-handed diode and a right-handed diode; when the operating state of the left-handed diode switches between the two states of being off and on, the reflection phase of the left-handed circularly polarized electromagnetic wave changes by 180°; when the operating state of the right-handed diode switches between the two states of being off and on, the reflection phase of the right-handed circularly polarized electromagnetic wave changes by 180°.

[0017] Furthermore, the states of the left-hand and right-hand diodes loaded on each programmable unit by the programmable metasurface can be controlled independently. The operating state of the left-hand diode will not affect the reflection phase of the right-hand circularly polarized electromagnetic wave, and the operating state of the right-hand diode will not affect the reflection phase of the left-hand circularly polarized electromagnetic wave.

[0018] Furthermore, when the programmable unit is pointed to 0° and 90°, the static code of the defined unit is "0" and "1" respectively; when the working state of the left-handed diode is off and on, the left-handed dynamic code of the defined unit is "0" and "1" respectively; when the working state of the right-handed diode is off and on, the right-handed dynamic code of the defined unit is "0" and "1" respectively.

[0019] Furthermore, the final encoding of the programmable unit depends on the unit's static encoding and dynamic encoding; when the static encoding is "0" and the left-hand dynamic encoding is "0" or "1", the final left-hand encoding is "0" or "1"; when the static encoding is "1" and the left-hand dynamic encoding is "0" or "1", the final left-hand encoding is "1" or "0"; when the static encoding is "0" and the right-hand dynamic encoding is "0" or "1", the final right-hand encoding is "0" or "1"; when the static encoding is "1" and the right-hand dynamic encoding is "0" or "1", the final right-hand encoding is "1" or "0"; the final left-hand encoding and the final right-hand encoding are independent of each other and can be designed simultaneously.

[0020] Furthermore, the left-hand and right-hand dynamic coding of all programmable units is controlled simultaneously and independently by a single field-programmable gate array (FPGA).

[0021] Furthermore, the near-field feed used by the programmable metasurface is a small-aperture linearly polarized horn antenna, which is placed above the center of the programmable metasurface, and the distance between the aperture surface of the horn antenna and the programmable metasurface is F.

[0022] Furthermore, the phase distribution design criteria for the programmable metasurface are as follows: (1), In the formula: i=1,2,…M, j=1,2,…N, M is the number of elements of the metasurface along the X-axis, N is the number of elements of the metasurface along the Y-axis, xij and yij are the two-dimensional coordinates of the ij-th programmable element, and φ and θ are the azimuth and elevation angles of the beam pointing.

[0023] Furthermore, the programmable metasurface discretizes the calculated random phase distribution into a 1-bit phase distribution and obtains the pointing angle of each unit according to the static encoding rules; it also discretizes the calculated reflection phase distributions of left-hand and right-hand circularly polarized electromagnetic waves into 1-bit phase distributions and calculates the left-hand and right-hand dynamic encoding distributions according to the final encoding rules. This obtains the operating state of each left-hand and right-hand diode, thereby simultaneously and independently controlling the left-hand and right-hand circularly polarized electromagnetic waves.

[0024] Secondly, this invention proposes a control method for a programmable metasurface that is simultaneously compatible with electromagnetic stealth and dynamic radiation, wherein the programmable metasurface is as described above; the control method includes the following steps: Simulations were conducted to obtain the relationships between the amplitude and phase of the reflection coefficient and the unit pointing angle, as well as the relationship between the amplitude and phase of the reflection coefficient and the unit pointing angle, and the relationship between the amplitude and phase of the reflection coefficient and the right-handed diode, under the conditions of left-handed and right-handed circularly polarized electromagnetic wave incidence. When a plane electromagnetic wave emitted by a far-field radar is incident on each unit, the random phase distribution that the metasurface needs to generate is calculated, and the corresponding 1-bit static code distribution is discretized to obtain the pointing angle of each unit. When spherical electromagnetic waves emitted by a near-field small-aperture linearly polarized horn antenna are incident on each element, the phase distribution required for metasurface-controlled left-hand and right-hand circularly polarized electromagnetic wave beams is calculated, and 1-bit left-hand and right-hand final coding distributions are discretized to obtain the corresponding 1-bit left-hand and right-hand dynamic coding distributions. Based on the left-hand and right-hand dynamic coding distributions, the working state switching scheme of each left-hand and right-hand diode is obtained, and the left-hand and right-hand circularly polarized electromagnetic waves are controlled by applying left-hand and right-hand bias voltages through the FPGA.

[0025] The advantages of this invention compared to existing technologies are as follows: First, this invention provides a programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation. On a single programmable metasurface platform, it successfully achieves real-time and efficient compatibility of two major functions: fully polarized electromagnetic stealth and dynamic electromagnetic radiation. When facing far-field arbitrary polarized plane wave detection, this metasurface can effectively suppress backscattered energy in all directions through random scattering, significantly reducing its radar cross-section and achieving excellent electromagnetic stealth. When receiving near-field spherical wave illumination from a near-field feed source, it can precisely reconstruct the direction of the reflected beam by real-time programming and controlling the state of each unit, achieving flexible and rapid dynamic radiation. This intelligent switching and coexistence of stealth and radiation states solves the contradictory requirement of traditional platforms that struggle to simultaneously address stealth and active radiation.

[0026] Secondly, compared to existing technologies, the programmable metasurface of this invention achieves dual performance optimization under the same electrical dimensions. On the one hand, it achieves a lower radar cross section (RCS) in stealth mode, significantly improving the platform's survivability and penetration capability. On the other hand, in radiation mode, its rapid beam scanning capability is not sacrificed due to the low RCS design, and it can still efficiently and agilely complete beamforming and pointing control, meeting the requirements of high-speed communication, precision detection, and other missions. This characteristic of maintaining high dynamic radiation performance under low observability conditions is a significant advantage that existing programmable metasurface technologies cannot match.

[0027] Third, the technical solution provided by this invention has broad application prospects and significant practical value. Its unique dual-mode compatibility allows for wide application in fields such as satellite communication (dynamic beam tracking), radar detection (active detection on low-observable platforms), electronic countermeasures (flexible jamming / deception under covert deployment), and high-performance beamforming systems. This platform can significantly improve the overall performance of related systems in complex electromagnetic environments, such as enhancing near-field communication / detection capabilities while reducing the risk of far-field detection, simplifying system architecture (a single platform replaces some separate stealth and radiating units), and providing core component support for a new generation of multifunctional, intelligent RF front-end systems. Attached Figure Description

[0028] Figure 1 A schematic diagram of a programmable metasurface that is compatible with both electromagnetic stealth and dynamic radiation; Figure 2 This is the top-level view of the programmable unit; Figure 3 This is a view of the third metal layer of the programmable cell; Figure 4 This is a view of the fourth metal layer of the programmable cell; Figure 5 The diagram shows the simulation results of the programmable unit; where (a) and (c) are the relationships between the amplitude and phase of the reflection coefficient of the left-hand circularly polarized electromagnetic wave and the states of the left-hand and right-hand diodes, respectively, when the programmable unit is rotated by 0° and 90°; (b) and (d) are the relationships between the amplitude and phase of the reflection coefficient of the right-hand circularly polarized electromagnetic wave and the states of the left-hand and right-hand diodes, respectively, when the programmable unit is rotated by 0° and 90°. Figure 6 View of a programmable metasurface and a linearly polarized horn antenna; Figure 7 Several coding distributions were obtained for optimization; among them, (a) is the static coding distribution; (b), (c), (d), (e), (f), (g) and (h) are the final coding distributions with beam pointing to -30°, -20°, -10°, 0°, +10°, +20° and +30°, respectively; Figure 8 The two-dimensional far-field radiation patterns of the programmable metasurface online polarized horn antenna are shown. Among them, (a) and (b) are the simulated two-dimensional far-field radiation patterns of left-handed and right-handed circularly polarized electromagnetic waves, respectively; (c) and (d) are the tested two-dimensional far-field radiation patterns of left-handed and right-handed circularly polarized electromagnetic waves, respectively.

[0029] Figure 9 This is a three-dimensional far-field pattern of a programmable metasurface under the incidence of an online polarized plane wave. Detailed Implementation

[0030] The following embodiments are provided to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0031] This invention proposes a programmable metasurface 1 that is compatible with both electromagnetic stealth and dynamic radiation. It consists of M×N programmable units, where M and N are positive integers. M is the number of units along the X-axis of the metasurface, and N is the number of units along the Y-axis of the metasurface. All programmable units have the same structure, but the units point at 0° or 90°.

[0032] When the programmable metasurface is detected by arbitrarily polarized planar electromagnetic waves emitted by the far-field radar 2, the metasurface can randomly scatter the electromagnetic energy of the incoming wave into various directions in space, making its own radar cross-section very small, thus achieving fully polarized electromagnetic stealth.

[0033] Under the illumination of spherical electromagnetic waves emitted by near-field feed 3, the programmable metasurface can control the state of diodes loaded on each programmable unit through FPGA4, thereby enabling real-time adjustment of the beam direction of the reflected electromagnetic waves and realizing dynamic electromagnetic radiation.

[0034] Compared with existing programmable metasurfaces, the programmable metasurface has a lower radar cross section for the same electrical size and can simultaneously achieve fully polarized electromagnetic stealth and dynamic electromagnetic radiation.

[0035] For arbitrary polarized plane electromagnetic waves emitted by far-field radar, the programmable metasurface generates relative phase delays of 0° and 180° for their circular polarization components, respectively, through programmable units pointing at 0° and 90°. The two electromagnetic waves with a phase difference of 180° coherently cancel each other out in the positive reflection direction. Furthermore, since the programmable units pointing at 0° and 90° are randomly arranged, the detection electromagnetic waves emitted by the far-field radar are randomly scattered into various directions in space by the programmable metasurface, significantly reducing the echo electromagnetic energy received by the far-field radar. In other words, the radar cross-section of the programmable metasurface detected by the far-field radar is very small, achieving fully polarized electromagnetic stealth.

[0036] Compared to a smooth metal plane of the same size, the programmable metasurface has a radar cross-section reduction of more than 10 dB, a center operating frequency of 10 GHz, and a relative bandwidth of more than 20%.

[0037] Each programmable unit is stacked from top to bottom as follows: first metal layer 5, first dielectric layer 6, second metal layer 7, prepreg layer 8, third metal layer 9, second dielectric layer 10, and fourth metal layer 11. A grounding first metal blind via 12 passes through the first dielectric layer 6, a left-handed first metal blind via 13 and a right-handed first metal blind via 14 pass through the first dielectric layer 6, the second metal layer 7, and the prepreg layer 8, and a left-handed second metal blind via 15 and a right-handed second metal blind via 16 pass through the second dielectric layer 10. A left-handed diode 17 is soldered to the left side of the first metal layer 5, and a right-handed diode 18 is soldered to the right side of the first metal layer 5. The third metal layer 9 of the programmable unit includes a left-handed fan-shaped metal patch 19, a right-handed fan-shaped metal patch 20, a left-handed first feed line 21, and a right-handed first feed line 22; the left-handed first metal feed line 21 is connected to the left side of the first metal layer 5 through a left-handed first metal blind hole 13, and the right-handed first metal feed line 22 is connected to the right side of the first metal layer 5 through a right-handed first metal blind hole 14.

[0038] The fourth metal layer 11 of the programmable unit includes a left-handed second metal feed line 23 and a right-handed second metal feed line 24. The left-handed second metal feed line 23 is connected to the left-handed first metal feed line 21 through a left-handed second metal blind via 15, and the right-handed second metal feed line 24 is connected to the right-handed first metal feed line 22 through a right-handed second metal blind via 16. A left-handed bias voltage is applied to the left-handed second metal feed line 23 to control the state of the left-handed diode 17, and a right-handed bias voltage is applied to the right-handed second metal feed line 24 to control the state of the right-handed diode 18.

[0039] The programmable unit has a cycle of 7.5 mm, the first dielectric layer 6 has a thickness of 3 mm, the prepreg layer 8 has a thickness of 0.2 mm, and the second dielectric layer 10 has a thickness of 1 mm. The dielectric constants of the first dielectric layer 6 and the second dielectric layer 10 are both 2.65 and the tangent loss angle is 0.001. The dielectric constant of the prepreg layer 8 is 3.52 and the tangent loss angle is 0.004.

[0040] The first metal layer 5 of the programmable unit covers the first dielectric layer 6 and has a square open ring structure. The middle part of the first metal layer 5 is connected to the ground first metal blind via 12. The left part of the first metal layer 5 is soldered with a left-handed diode 14, the right part of the first metal layer 5 is soldered with a right-handed diode 18, the left part of the first metal layer 5 is connected to a left-handed first metal blind via 13, and the right part of the first metal layer 5 is connected to a right-handed first metal blind via 14.

[0041] Each programmable unit of the programmable metasurface is loaded with a left-handed diode and a right-handed diode. When the operating state of the left-handed diode switches between the two states of being off and on, the reflection phase of the left-handed circularly polarized electromagnetic wave changes by 180°. When the operating state of the right-handed diode switches between the two states of being off and on, the reflection phase of the right-handed circularly polarized electromagnetic wave changes by 180°.

[0042] The states of the left-hand and right-hand diodes loaded on each programmable unit by the programmable metasurface can be controlled independently. The operating state of the left-hand diode does not affect the reflection phase of the right-hand circularly polarized electromagnetic wave, and the operating state of the right-hand diode does not affect the reflection phase of the left-hand circularly polarized electromagnetic wave.

[0043] When the programmable unit points to 0° and 90°, the static code of the unit is defined as “0” and “1”, respectively; when the left-handed diode is in the off and on state, the left-handed dynamic code of the unit is defined as “0” and “1”, respectively; when the right-handed diode is in the off and on state, the right-handed dynamic code of the unit is defined as “0” and “1”, respectively.

[0044] The final encoding of a programmable unit depends on its static and dynamic encoding. When the static encoding is "0" and the left-hand dynamic encoding is "0" or "1", the final left-hand encoding is "0" or "1". When the static encoding is "1" and the left-hand dynamic encoding is "0" or "1", the final left-hand encoding is "1" or "0". When the static encoding is "0" and the right-hand dynamic encoding is "0" or "1", the final right-hand encoding is "0" or "1". When the static encoding is "1" and the right-hand dynamic encoding is "0" or "1", the final right-hand encoding is "1" or "0". The final left-hand encoding and the final right-hand encoding are independent of each other and can be designed simultaneously.

[0045] The left-hand and right-hand dynamic coding of all programmable units is controlled simultaneously and independently by a single field-programmable gate array (FPGA).

[0046] The following detailed description, with reference to the accompanying drawings, describes a programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation, as proposed in this invention: like Figure 2 As shown, thanks to the design of the square open ring in the first metal layer of the metasurface and the design of the metallized blind via, the operating state of the left-handed diode does not affect the reflection phase of the right-handed circularly polarized electromagnetic wave, and the operating state of the right-handed diode does not affect the reflection phase of the left-handed circularly polarized electromagnetic wave. Therefore, independent dual-circular polarization reflection phase control can be obtained, making the left-handed and right-handed dynamic phase encoding schemes independent of each other. The bias voltage of all diodes on the programmable metasurface is controlled by the FPGA, so the left-handed and right-handed circular polarization dynamic encoding schemes can be switched in real time via the FPGA.

[0047] like Figure 3 and Figure 4 As shown, when the left-hand and right-hand diodes are independently biased, a fan-shaped stub is added at the bias line to isolate the leakage of high-frequency current, so that the unit has good reflection efficiency.

[0048] like Figure 5 As shown, the unit was simulated using the commercial electromagnetic simulation software CST Microwave Studio. The relationships between the amplitude and phase of the reflection coefficient and the variations of the left-handed and right-handed circularly polarized electromagnetic waves, as well as the structural rotation angle, were obtained under the conditions of left-handed and right-handed circularly polarized electromagnetic wave incidence. like Figure 6 As shown, the programmable metasurface uses a small-aperture linearly polarized horn antenna as an RF feed. The horn antenna is placed above the center of the programmable metasurface, and the distance between the two is F=120mm.

[0049] The phase distribution design criteria for the programmable metasurface are as follows: (1), In the formula: i, j are the element indices on the metasurface, i=1,2,…M, j=1,2,…N, M is the number of elements on the metasurface along the X-axis, N is the number of elements on the metasurface along the Y-axis, x ij and y ij Let φ be the two-dimensional coordinates of the i-th and j-th programmable units, and φ and θ be the azimuth and elevation angles of the beam.

[0050] At a frequency of 10 GHz, the phase distribution of the incident wave upon arrival at each unit is calculated. The reflected phase calculated according to this formula can form a far-field pencil beam or a randomly scattered beam in the reflection region. In this invention, the far-field pencil beam pointing of left-handed and right-handed circularly polarized electromagnetic waves can be designed independently, enabling independent beam scanning.

[0051] like Figure 7 As shown, the programmable metasurface discretizes the calculated random phase distribution into a 1-bit phase distribution and obtains the structural rotation angle of each programmable unit according to the static encoding rules; the programmable metasurface discretizes the calculated reflection phase distribution of left-handed and right-handed circularly polarized electromagnetic waves into a 1-bit phase distribution, calculates the left-handed and right-handed dynamic encoding distribution according to the final encoding rules, and obtains the working state of each left-handed and right-handed diode, thereby simultaneously and independently controlling the left-handed and right-handed circularly polarized electromagnetic waves.

[0052] like Figure 8As shown, the simulation and test results of the two-dimensional far-field radiation pattern of the programmable metasurface under spherical wave incident are presented. It can be clearly observed that the pointing of the left-hand and right-hand spiral beams obtained from the simulation and test matches the pre-designed angle, reflecting the good dual-circular polarization dynamic scanning capability of the programmable metasurface.

[0053] like Figure 9 As shown, the simulation results of the three-dimensional far-field radiation pattern of the programmable metasurface under the incident plane wave with online polarization are presented. It can be clearly observed that in the range of 9.4 GHz to 10.6 GHz, the programmable metasurface can randomly scatter the incident electromagnetic wave energy into various directions in space, reflecting the good broadband low RCS performance of the programmable metasurface and its excellent stealth capability.

[0054] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation, characterized in that: The programmable metasurface (1) consists of M×N programmable units, where M is the number of units along the X-axis of the metasurface and N is the number of units along the Y-axis of the metasurface. All programmable units have the same geometric structure, and the programmable units point at 0° or 90°.

2. The programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation according to claim 1, characterized in that: The programmable metasurface has a radar cross-sectional area reduction of more than 10 dB, a center operating frequency of 10 GHz, and a relative bandwidth of more than 20%.

3. The programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation according to claim 1, characterized in that: Each programmable unit is loaded with a left-handed diode and a right-handed diode. When the left-handed diode switches between the two states of being off and on, the reflected phase of the left-handed circularly polarized electromagnetic wave changes by 180°. When the right-handed diode switches between the two states of being off and on, the reflected phase of the right-handed circularly polarized electromagnetic wave changes by 180°.

4. A programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation according to claim 1, characterized in that: The left-hand and right-hand dynamic coding of all programmable units is controlled simultaneously and independently by a single field-programmable gate array (FPGA).

5. A programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation according to claim 1, characterized in that: The near-field feed used by the programmable metasurface is a small-aperture linearly polarized horn antenna, which is placed above the center of the programmable metasurface. The distance between the aperture surface of the horn antenna and the programmable metasurface is F.

6. A programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation according to claim 1, characterized in that: The phase distribution design criteria for the programmable metasurface are as follows: （1）， In the formula: i = 1, 2, ..., M, j = 1, 2, ..., N, M is the number of elements along the X-axis of the metasurface, N is the number of elements along the Y-axis of the metasurface, x ij and y ij Let φ be the two-dimensional coordinates of the ij-th programmable unit, and φ and θ be the azimuth and elevation angles of the beam pointing.

7. A programmable metasurface that simultaneously supports electromagnetic stealth and dynamic radiation according to claim 6, characterized in that: The calculated random phase distribution is discretized into a 1-bit phase distribution, and the pointing angle of each unit is obtained according to the static coding rule. The calculated reflection phase distribution of left-hand and right-hand circularly polarized electromagnetic waves is discretized into a 1-bit phase distribution, and the left-hand and right-hand dynamic coding distribution is calculated according to the final coding rule to obtain the working state of each left-hand and right-hand diode, thereby simultaneously and independently controlling the left-hand and right-hand circularly polarized electromagnetic waves.

8. A control method for a programmable metasurface that is simultaneously compatible with electromagnetic stealth and dynamic radiation, characterized in that: The programmable metasurface is the programmable metasurface as described in any one of claims 1-7; the control method includes the following steps: Simulations were conducted to obtain the relationships between the amplitude and phase of the reflection coefficient and the unit pointing angle, as well as the relationship between the amplitude and phase of the reflection coefficient and the unit pointing angle, and the relationship between the amplitude and phase of the reflection coefficient and the right-handed diode, under the conditions of left-handed and right-handed circularly polarized electromagnetic wave incidence. When a plane electromagnetic wave emitted by a far-field radar is incident on each unit, the random phase distribution that the metasurface needs to generate is calculated, and the corresponding 1-bit static code distribution is discretized to obtain the pointing angle of each unit. When a spherical electromagnetic wave emitted by a near-field linearly polarized horn antenna is incident on each element, the phase distribution required for the metasurface to control the left-hand and right-hand circularly polarized electromagnetic wave beams is calculated, and a 1-bit left-hand and right-hand final coding distribution is generated discretely, thereby obtaining the corresponding 1-bit left-hand and right-hand dynamic coding distribution. Based on the left-hand and right-hand dynamic coding distribution, the working state switching scheme of each left-hand and right-hand diode is obtained, and the left-hand and right-hand circularly polarized electromagnetic waves are controlled by applying left-hand and right-hand bias voltages through the FPGA.

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