Tunable low-profile dual-polarized a-t-a absorptive metasurfaces and radomes

Abstract

The application belongs to the technical field of controllable metamaterials and radomes, and particularly relates to a controllable low-profile dual-polarized A-T-A absorbing and transmissive metasurface and radome, which comprises an absorbing screen and a transmissive screen arranged in layers; the absorbing screen comprises a plurality of periodically arrayed absorbing screen units, each of which comprises a dielectric substrate I, a metal foil micro-unit attached to the upper surface of the dielectric substrate I, and an energy consumption piece loaded on the metal foil micro-unit; the application improves the RCS reduction effect of metal, enables the antenna to maintain good radiation characteristics in the Ku band, and enables free communication; meanwhile, the application has good absorbing performance in the X band and the Ku band on both sides of the passband, reduces the RCS of the antenna, and achieves the stealth purpose of the antenna.

Description

Technical Field

[0001] The present invention belongs to the technical field of adjustable metamaterials and antenna covers, and in particular relates to an adjustable low-profile dual-polarized ATA absorbent metasurface and an antenna cover. Background Art

[0002] Metamaterial structured surfaces with wave-absorbing and wave-transmitting functions (referred to as "metasurfaces") have great application prospects in radar and communication systems. They can be used on radar system antenna covers to improve the radiation and stealth performance of radar antennas; they can also be used in the communication field to form controllable metasurfaces to achieve information control.

[0003] The transmission band of a metasurface is called the transmission band, or T-band for short; its absorption band is called the absorptive band, or A-band for short. Based on the relative positions of the T-band and A-band on the spectrum, metasurfaces can be divided into two main categories. The first category has one transmission band and one absorption band within the frequency band, known as the AT or TA type. The second category has the transmission band located in the middle of the absorption band, known as the ATA type.

[0004] Currently, the absorption theory of metasurfaces is based on the principle of Salisbury screen absorption. This requires at least one absorbing screen and one transparent screen, with the spacing between the two screens being one-quarter the wavelength of the center frequency in the operating band. When a metasurface achieves controllable functionality, each unit needs to be fed with DC power. These DC feed lines, which are unavoidable for controllable metasurfaces, act as resistive or reactive elements within the RF microwave band, significantly impacting the electromagnetic performance of the metasurface. Furthermore, there are few examples in published literature of a single metasurface replacing either an absorbing or a transparent screen, such as combining an absorbing screen with two different transparent screens to form two different metasurfaces. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an adjustable low-profile dual-polarization ATA absorbent metasurface and antenna cover, which improves the RCS reduction effect on metals, enables the antenna to maintain good radiation characteristics in the Ku band, and can freely transmit and receive communications; at the same time, it has good absorption performance in the X band and Ku band on both sides of the passband, thereby reducing the RCS of the antenna and achieving the purpose of stealth.

[0006] The embodiment of the present invention provides a controllable low-profile dual-polarization ATA absorbing and transmitting metasurface, comprising a stacked absorbing screen and a transmitting screen;

[0007] The wave absorbing screen comprises a plurality of wave absorbing screen units distributed in a periodic array, wherein the wave absorbing screen unit comprises a dielectric substrate I, a metal foil micro unit attached to the upper surface of the dielectric substrate I, and an energy dissipation component loaded on the metal foil micro unit;

[0008] The metal foil micro-unit is formed by bending and closing a metal wire, and includes at least two metal rods symmetrically distributed around the center point of the dielectric substrate I. The metal rods are composed of two parallel metal wires, and the metal rods include a main rod and at least two branch rods perpendicular to the main rod.

[0009] The energy dissipation component is arranged at the center of the branch rod, and the energy dissipation component includes two metal patches arranged opposite to each other and a resistor located between the metal patches.

[0010] Preferably, there are four metal rods and four branch rods.

[0011] Preferably, extending outward from the center point of the dielectric substrate I, the length of the branch rods first increases and then decreases, with the longest branch rod being located at the outermost side.

[0012] Preferably, the dielectric substrate I in the absorbing screen unit is square with a side length of 8-12 mm, the thickness of the dielectric substrate I is 0.1-1 mm, the dielectric constant of the dielectric substrate I is 2.2-3.66, the thickness of the metal foil microunit is 0.017-0.035 mm, the width of the metal wire is 0.1-0.3 mm, and the distance between two parallel metal wires is 0.2-0.5 mm.

[0013] Preferably, the wave-transmitting screen includes a plurality of wave-transmitting screen units I distributed in a periodic array, the wave-transmitting screen unit I includes a dielectric substrate II and a metal foil attached to the upper surface of the dielectric substrate II, the metal foil is provided with rectangular slits, and the dielectric substrate II on the wave-transmitting screen unit I and the dielectric substrate I on the wave-absorbing screen unit are bonded together.

[0014] Preferably, the distance between the dielectric substrate II on the wave-transmitting screen unit I and the dielectric substrate I on the wave-absorbing screen unit is 1-4 mm.

[0015] Preferably, the wave-transmitting screen comprises a plurality of wave-transmitting screen units II distributed in a periodic array, and the wave-transmitting screen unit II comprises a lower metal foil micro-unit, a dielectric substrate III, a middle metal foil micro-unit, a dielectric substrate IV and an upper metal foil micro-unit stacked in sequence;

[0016] The lower metal foil micro-unit and the upper metal foil micro-unit have the same structure, including a central metal foil and a peripheral metal foil that do not contact each other, two trapezoidal areas etched on the peripheral metal foil with the central metal foil as the symmetric center, the trapezoidal areas are in direct contact with the central metal foil, and a varactor diode is connected between the peripheral metal foil and the central metal foil in the non-etched trapezoidal areas;

[0017] The trapezoidal regions of the lower metal foil micro-unit and the upper metal foil micro-unit do not overlap each other;

[0018] The middle metal foil micro-unit includes two intersecting metal lines, and the intersection of the metal lines connects the lower metal foil micro-unit and the upper metal foil micro-unit.

[0019] Preferably, two symmetrically arranged gaps located on the side of the varactor diode are etched on the central metal foil.

[0020] Preferably, the short side of the trapezoidal area is closer to the central metal foil than the long side of the trapezoidal area, and further comprises an adhesive sheet for bonding the dielectric substrate III and the dielectric substrate IV.

[0021] An embodiment of the present invention provides a radome comprising the adjustable low-profile dual-polarization ATA absorbent metasurface.

[0022] The "adjustable" designation refers to the fact that a single absorbing screen can be combined with two different transparent screens to form either an unadjustable or an adjustable dual-polarized absorptive metasurface. The first "A" in "ATA" refers to the low-frequency absorbing band, the T to the transparent band, and the second "A" to the high-frequency absorbing band. The absorptive metasurface of this application can exhibit all of these characteristics simultaneously.

[0023] The beneficial effect of the present invention is that it is difficult for existing adjustable metasurfaces to avoid the DC feeder problem, and all metasurfaces have fixed absorbing screens and transparent screens. The present invention designs two metasurfaces, and the absorbing screens of these two metasurfaces are the same. The difference is that one of the transparent screens has a simple structural unit that cannot be adjusted, while the other transparent screen has an adjustable function.

[0024] The uncontrollable or controllable dual-polarized absorbent metasurface of the present invention enables the antenna to maintain good radiation characteristics in the Ku band, enabling free transmission and reception of communications; at the same time, it has good wave absorption performance in the X band and Ku band on both sides of the passband, reducing the RCS of the antenna and achieving the purpose of antenna stealth. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a two-dimensional side view schematic diagram of the square unit structure of the uncontrollable absorbent metasurface of Example 1 of the present invention; the rectangular coordinate system xyz represents the spatial relationship.

[0026] Figure 2 This is a two-dimensional top view schematic diagram of the metal foil micro-unit of the absorbing screen according to Example 1 of the present invention.

[0027] Figure 3 This is a two-dimensional top view schematic diagram of the wave-transmitting screen unit I according to Example 1 of the present invention.

[0028] Figure 4 3D schematic diagram of the square unit structure of the non-adjustable absorbent metasurface according to Example 1 of the present invention.

[0029] Figure 5 Schematic diagram of the equivalent circuit model of a square unit structure of a non-adjustable translucent metasurface according to Example 1 of the present invention. (a) is the electromagnetic model of the non-adjustable translucent metasurface, and (b) is the equivalent circuit model of (a).

[0030] Figure 6 Schematic diagram of a two-dimensional side view of a square unit structure of an adjustable absorbent metasurface according to Example 2 of the present invention.

[0031] Figure 7 This is a two-dimensional top view schematic diagram of the lower metal foil micro-unit of Example 2 of the present invention.

[0032] Figure 8 This is a two-dimensional top view schematic diagram of the upper metal foil micro-unit of Example 2 of the present invention.

[0033] Figure 9 This is a two-dimensional top view schematic diagram of the metal foil microunit in Example 2 of the present invention.

[0034] Figure 10 Schematic diagram of a three-dimensional side view of a square unit structure of an adjustable absorbent metasurface according to Example 2 of the present invention.

[0035] Figure 11 3D schematic diagram of the square unit structure of the controllable absorbent metasurface according to Example 2 of the present invention.

[0036] Figure 12 Schematic diagram of the equivalent circuit model of the square unit structure of the adjustable absorbent metasurface according to Example 2 of the present invention. (a) is the electromagnetic model of the adjustable absorbent metasurface, and (b) is the equivalent circuit model of (a).

[0037] Figure 13 Schematic diagram of metallized through holes 022134 and 022135 on the periodic structure 022 of the controllable metasurface of the square unit structure of the controllable absorption metasurface according to Example 2 of the present invention.

[0038] Figure 14 The transmission / reflection coefficient simulation results for the square unit structure of the non-adjustable transmissive absorptive metasurface of Example 1 of the present invention are shown. The structure has a transmission passband of 12.9 GHz to 14.8 GHz, a first absorption band of 9.3 GHz to 12.1 GHz, and a second absorption band of 15.7 GHz to 18.1 GHz.

[0039] Figure 15These are the transmission / reflection coefficient simulation results for the square unit structure of the tunable transmissive metasurface according to Example 2 of the present invention. The structure has a transmission passband of 14.5 GHz to 16.1 GHz, a first absorption band of 10.3 GHz to 13.5 GHz, and a second absorption band of 17.2 GHz to 24 GHz.

[0040] Figure 16 Simulation results of the transmission / reflection coefficients of the square unit structure of the tunable transmissive metasurface, shown in Example 2 of the present invention, as the capacitance of the varactor changes. As can be seen from the figure, as the capacitance of the varactor increases, the structure's transmission band shifts toward lower frequencies, and the reflection coefficient decreases.

[0041] Figure 17 The following are the single-station RCS simulation results for a pure metal plate, the non-adjustable translucent metasurface of Example 1, and the adjustable translucent metasurface of Example 2, all with an area of ​​100 mm × 100 mm. As can be seen from the figure, within the metasurface's operating frequency band, both structures can effectively reduce the single-station RCS of the pure metal plate. The non-adjustable translucent metasurface achieves its maximum reduction of 30 dB at 10.8 GHz. The adjustable translucent metasurface achieves its maximum reduction of 43 dB at 12.8 GHz. This demonstrates that both structures significantly reduce the RCS of metals.

[0042] Figure 18 This is the S-curve simulation result of the square unit structure of the controllable absorbent metasurface of Example 2 of the present invention.

[0043] Figure 19 This is a two-dimensional top view schematic diagram of the metal foil micro-unit of the square unit structure of the absorbing screen of the controllable absorbent metasurface of Example 3 of the present invention.

[0044] Figure 20 This is the S-curve simulation result of the square unit structure of the controllable absorbent metasurface of Example 3 of the present invention.

[0045] In the figure, 1 is an absorbing screen unit, 11 is a dielectric substrate I, 12 is a metal foil micro unit, and 13 is an energy dissipation component;

[0046] 2 wave-transmitting screen unit I, 21 metal foil, 211 rectangular slit, 22 dielectric substrate II;

[0047] 121 metal wire, 122 main rod, 123 branch rod;

[0048] 131 metal patch, 132 resistor;

[0049] 3 wave-transmitting screen unit II, 31 lower metal foil microunit, 32 dielectric substrate III, 33 adhesive sheet, 34 middle metal foil microunit, 35 dielectric substrate IV, 36 upper metal foil microunit;

[0050] 311 center metal foil, 3111 gap, 312 peripheral metal foil, 313 trapezoidal region, 314 varactor diode;

[0051] 341 metal wire, 342 intersection point. DETAILED DESCRIPTION

[0052] Example 1

[0053] like Figure 1-5 As shown, a low-profile dual-polarization ATA absorbing and transmitting metasurface includes a stacked absorbing screen and a transmitting screen;

[0054] The absorbing screen includes a plurality of absorbing screen units 1 distributed in a periodic array, and the absorbing screen unit 1 includes a dielectric substrate Ⅰ 11, a metal foil micro unit 12 attached to the upper surface of the dielectric substrate Ⅰ 11, and an energy dissipation component 13 loaded on the metal foil micro unit 12;

[0055] The metal foil micro unit 12 is formed by bending and closing a metal wire 121, and includes four metal rods symmetrically distributed around the center point of the dielectric substrate I 11. The metal rods are composed of two parallel metal wires 121, each of which includes a main rod 122 and four branch rods 123 perpendicular to the main rod 122.

[0056] The energy dissipation component 13 is disposed at the center of the branch rod 123 . The energy dissipation component 13 includes two oppositely disposed metal patches 131 and a resistor 132 located between the metal patches 131 . The impedance of the resistor 132 is 200 ohms to 800 ohms.

[0057] A capacitor is formed between two opposing metal patches 131. A pair of metal patches 131 serve as the two plates of a capacitor. Metal patches 131 also serve as solder pads for resistor 132, facilitating soldering resistor 132 to metal wire 121. The capacitor formed between the two metal patches 131, with the resistor connected across the two metal patches 131, is equivalent to a parallel capacitor and resistor structure.

[0058] Extending outward from the center of dielectric substrate I11, the length of the rods 123 increases first and then decreases, with the longest rod 123 located on the outermost side. There are four rods 123, extending outward from the center of dielectric substrate I11 in directions designated as rods ad, with rod d being the longest and rod b being the second longest. Rods a and c can be the same length.

[0059] Two energy-absorbing components 13 are provided on each metal rod, that is, each absorbing screen unit 1 is provided with eight energy-absorbing components. One energy-absorbing component 13 is located on the outermost and longest branch rod d, and the other energy-absorbing component 13 is located between the second and third branches, that is, between the branches b and c. The metal patch of the energy-absorbing component 13 is rectangular, and the two ends of the rectangle are respectively on the branches b and c.

[0060] The metal foil micro-units 12 are preferably formed by bending a metal wire 121. The pattern formed by the bent wire is symmetrically distributed around the center point of the dielectric substrate 111. The pattern is composed of two oppositely positioned metal wires (i.e., metal rods), like hollow Chinese characters. The metal rods include a main rod 122 and four branch rods 123 perpendicular to the main rod 122. The metal wires 121 on the main rod 122 and the branch rods 123 are symmetrically distributed, and the two branch rods 123 are symmetrically arranged around the main rod 122. Therefore, the entire pattern is symmetrically distributed around the center point of the dielectric substrate 111.

[0061] The dielectric substrate I11 in the absorbing screen unit is square with a side length of 8-12 mm, a thickness of 0.1-1 mm, a dielectric constant of 2.2-3.66, a thickness of the metal foil microunit 12 of 0.017-0.035 mm, a width of the metal wire 121 of 0.1-0.3 mm, and a distance between two parallel metal wires 121 of 0.2-0.5 mm.

[0062] In the first embodiment, the metal patch 131 is a rectangular metal patch, and the side length of the rectangle is 0.3 mm to 1 mm.

[0063] The wave-transmitting screen includes a plurality of wave-transmitting screen units I2 distributed in a periodic array. The wave-transmitting screen unit I2 includes a dielectric substrate II 22 and a metal foil 21 attached to the upper surface of the dielectric substrate II 22. The metal foil 21 is provided with rectangular slits 211. The dielectric substrate II 22 on the wave-transmitting screen unit I2 and the dielectric substrate I11 on the wave-absorbing screen unit 1 are bonded together.

[0064] The distance between dielectric substrate II 22 on the transparent screen unit I 2 and dielectric substrate I 11 on the absorbing screen unit 1 (i.e., the distance between the absorbing screen and the transparent screen) is 1-4 mm. Dielectric substrate II 22 has a thickness of 0.1-1 mm and a dielectric constant of 2.2-3.66. Dielectric substrates I 11 and II 22 are made of the same material and have the same dimensions.

[0065] The wave absorbing screen unit 1 and the wave transmitting screen unit I2 of the present invention are both square, which facilitates array connection.

[0066] The absorbing screen of this embodiment 1 has two functions: 1. In the wave transmission frequency band, the structure transmits both TE and TM polarized incident electromagnetic waves; 2. In the wave absorption frequency band, the structure absorbs the energy of the two polarized incident electromagnetic waves by using resistance.

[0067] The wave-transmitting screen of the first embodiment has two functions: 1. In the wave-transmitting frequency band, the structure transmits both polarized electromagnetic waves; 2. In the wave-absorbing frequency band, the structure reflects both polarized electromagnetic waves.

[0068] Example 2

[0069] like Figure 6-13 As shown, a low-profile dual-polarization ATA absorbing and penetrating metasurface includes a stacked absorbing screen and a wave-transmitting screen, and the structure of the absorbing screen is as shown in Example 1.

[0070] The wave-transmitting screen comprises a plurality of wave-transmitting screen units II3 distributed in a periodic array, wherein the wave-transmitting screen unit II3 comprises a lower metal foil micro-unit 31, a dielectric substrate III 32, a middle metal foil micro-unit 34, a dielectric substrate IV 35 and an upper metal foil micro-unit 36 ​​which are stacked in sequence;

[0071] The lower metal foil micro-unit 31 and the upper metal foil micro-unit 36 ​​have the same structure, including a central metal foil 311 and a peripheral metal foil 312 that are not in contact with each other (i.e., the two metal foils are in an electrically open state). Two trapezoidal regions 313 are etched on the peripheral metal foil 312, symmetrically centered about the central metal foil 311. The trapezoidal regions 313 are in direct contact with the central metal foil 311. A varactor diode 314 is connected between the peripheral metal foil 312 and the central metal foil 311 where the trapezoidal regions 313 are not etched.

[0072] The trapezoidal regions of the lower metal foil micro-unit 31 and the upper metal foil micro-unit 36 ​​do not overlap each other;

[0073] The middle metal foil micro-unit 34 includes two intersecting (preferably perpendicular) metal lines 341 , and an intersection 342 of the metal lines 341 connects the lower metal foil micro-unit 31 and the upper metal foil micro-unit 36 ​​.

[0074] Two symmetrically arranged slits 3111 are etched on the central metal foil 311 and are located on the side of the varactor diode 314 .

[0075] The short side of the trapezoidal region 313 is closer to the central metal foil 311 than the long side of the trapezoidal region 313 . The trapezoidal region 313 also includes an adhesive sheet 33 (made of PP sheet with a relative dielectric constant of 3) for bonding the dielectric substrate III 32 and the dielectric substrate IV 35 .

[0076] like Figure 7As shown, the wave-transmitting screen unit II3 is a square, and the central metal foil 311 and the peripheral metal foil 312 do not contact each other, which means that a rectangular blank area is etched on the square metal foil (i.e. Figure 7 The width of the rectangular blank area is 0.1-0.3 mm.

[0077] The outer metal foil 312 is divided into four parts by the central metal foil 311, namely, the upper, lower, left and right parts. In the two opposite parts, such as Figure 7 Trapezoidal regions 313 are etched on the upper and lower parts (i.e., the trapezoidal region 313 has no metal foil). The parallel sides of the trapezoidal region 313 are parallel to the sides of the square (transparent screen unit II 3). Its short side is close to the central metal foil 311, and its long side is close to the side length of the square. Metal foil is also provided between the long side of the trapezoidal region 313 and the side of the square, i.e., the trapezoidal region 313 is located inside the metal foil.

[0078] A varactor diode 314 is connected between the outer metal foil 312 and the central metal foil 311 of the unetched trapezoidal region 313. Figure 7 As shown, the outer metal foil 312 of the unetched trapezoidal area 313 refers to the outer metal foil 312 on the left and right sides, that is, a varactor diode 314 is connected between the outer metal foil 312 on the left and right sides and the central metal foil 311 respectively, and the number of the varactor diodes 314 is two.

[0079] The central metal foil 311 is etched with two symmetrically arranged gaps 3111 located on the side of the varactor diode 314. Figure 7 As shown, there are two slots 3111, one close to the left and the other close to the outer metal foil 312. The slots 3111 reduce the resonant frequency, that is, the operating frequency of the wave-transmitting screen.

[0080] The wave-transmitting screen of Example 2 has an adjustable function.

[0081] The dielectric substrate in the wave-transmitting screen of Example 2 and the dielectric substrate in the wave-absorbing screen have the same dielectric constant but different thicknesses.

[0082] The intersection point 342 of the second embodiment is a through hole, which connects the lower metal foil micro unit 31 and the upper metal foil micro unit 36 ​​and is connected to a DC voltage source for regulating the varactor diode 314 .

[0083] The trapezoidal region 313 and the unetched peripheral metal foil 312 (ie Figure 7 The shape and size of the outer metal foil 312 of the left and right parts are the same. The trapezoidal areas of the lower metal foil micro unit 31 and the upper metal foil micro unit 36 ​​do not overlap each other. Figure 7-8As shown, when the lower metal foil micro-unit 31 and the upper metal foil micro-unit 36 ​​are stacked, since the trapezoidal region 313 and the unetched peripheral metal foil 312 have the same shape and size, the trapezoidal region 313 of the lower metal foil micro-unit 31 corresponds to the unetched peripheral metal foil 312 portion of the upper metal foil micro-unit 36. Figure 7 The left and right parts) correspond to the position of the trapezoidal area 313 of the upper metal foil micro unit 36 ​​(ie Figure 8 That is, the lower metal foil micro-unit 31 is rotated 90° relative to the upper metal foil micro-unit 36 ​​about the center of the wave-transmitting screen.

[0084] The wave-transmitting screen of Example 2 has three functions: 1. In the wave-transmitting frequency band, the structure realizes the transmission function of two polarized electromagnetic waves; 2. The wave-transmitting frequency band is adjustable by using varactor diodes; 3. In the wave-absorbing frequency band, the structure realizes the reflection function of two polarized electromagnetic waves.

[0085] The wave-transmitting screen unit II3 is a square with a side length of 8-12 mm, and the distance between the wave-absorbing screen and the wave-transmitting screen is 1-4 mm.

[0086] The thickness of the dielectric substrate III 32 and the dielectric substrate IV 35 is 0.1-1 mm, and the relative dielectric constant is 2.2-3.66.

[0087] The thickness of the lower metal foil micro-unit 31, the middle metal foil micro-unit 34 and the upper metal foil micro-unit 36 ​​are 0.017-0.035 respectively.

[0088] The central metal foil 311 is a square with a side length of 3-7 mm, the long side of the trapezoidal region is 6-9 mm, the short side is 3.5-5 mm, and the height is 3-7 mm. The length of the gap 3111 is 2-4 mm.

[0089] The capacitance value of the varactor diode varies from 0.2 pF to 3 pF, and the applied DC voltage is from 4 V to 22 V.

[0090] like Figure 13 As shown, the positive pole of the DC voltage source is connected to the intersection point 342 in one of the wave-transmitting screen units II3 (located on the periphery of the wave-transmitting metasurface) in the low-profile dual-polarization ATA absorptive metasurface, and the negative pole of the DC voltage source is connected to the intersection point 342 in another wave-transmitting screen unit II3 (located on the periphery of the wave-transmitting metasurface), thereby forming a closed loop.

[0091] The present invention also provides a radome for covering the radiation direction of the antenna system, wherein the radome is composed of the non-adjustable embodiment 1 or the adjustable transmissive metasurface of embodiment 2.

[0092] The dielectric substrate is made of a non-conductive material with a relative dielectric constant of 2.2 and a dielectric loss of 0.0009. The metal foil layer can be made of any of gold foil, silver foil, or copper foil.

[0093] In the microwave studio of CST, a 3D high-frequency electromagnetic simulation software, the simulation results of the transmission / reflection coefficients (T / R coefficients) varying with frequency were obtained when a uniform plane wave was incident on the electromagnetic model and circuit model of the two metasurface structures. Figure 14 and Figure 15 shown.

[0094] Figure 16 To change the capacitance of a varactor diode, CST simulates the frequency-dependent transmission / reflection coefficients (T / R coefficients) of the variable-capacitance diode using an electromagnetic model of the tunable metasurface.

[0095] Figure 17 The single-station RCS simulation results are obtained by using CST to model a pure metal plate, a non-adjustable metasurface, and an adjustable metasurface with an area of ​​100 mm × 100 mm.

[0096] As shown in the figure, within the operating frequency band of the metasurface, both structures can effectively reduce the single-station RCS of a pure metal plate. The non-tunable metasurface achieves its maximum reduction of 30 dB at 10.8 GHz, while the tunable metasurface achieves its maximum reduction of 43 dB at 12.8 GHz. This demonstrates that both structures significantly reduce the RCS of metals.

[0097] Figure 18 This is the S-curve simulation result of the square unit structure of the tunable wave-absorbing metasurface according to Example 1 of the present invention. Within the frequency band between markers 1 and 2, the structure exhibits low-frequency wave-absorbing characteristics; within the frequency band between markers 3 and 4, the structure exhibits high-frequency wave-absorbing characteristics; and within the frequency band between markers 5 and 6, the structure exhibits wave-transmitting characteristics.

[0098] Example 3

[0099] like Figure 19 As shown, a low-profile dual-polarized ATA absorbing and penetrating metasurface includes a stacked absorbing screen and a transparent screen, wherein the two-dimensional top view schematic diagram of the metal foil micro-unit of the absorbing screen is shown in FIG. Figure 19 As shown, the lengths of the branch rods 123 increase sequentially from the center point of the dielectric substrate Ⅰ 11 outward, with the longest branch rod 123 located at the outermost side.

[0100] The structure of the wave-transmitting screen is as follows Figure 2 shown.

[0101] The S-curve simulation results are as follows: Figure 20 As shown in the figure, within the frequency band between markers 1 and 2, the structure exhibits low-frequency wave absorption characteristics; within the frequency band between markers 3 and 4, the structure exhibits high-frequency wave absorption characteristics. However, within the frequency band between markers 5 and 6, the wave transmission characteristics of the structure are not ideal.

[0102] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0103] The one or more embodiments of this application are intended to encompass all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application should be included in the scope of protection of this application.

Claims

1. A tunable low-profile dual-polarized ATA absorbent metasurface, characterized by: It includes a wave-absorbing screen and a wave-transmitting screen arranged in layers; The wave absorbing screen comprises a plurality of wave absorbing screen units (1) distributed in a periodic array, wherein the wave absorbing screen unit (1) comprises a dielectric substrate I (11), a metal foil micro unit (12) attached to the upper surface of the dielectric substrate I (11), and an energy dissipation component (13) loaded on the metal foil micro unit (12); The metal foil micro unit (12) is formed by bending and closing a metal wire (121), and includes at least two metal rods symmetrically distributed around the center point of the dielectric substrate I (11), the metal rods being composed of two parallel metal wires (121), and the metal rods including a main rod (122) and four branch rods (123) perpendicular to the main rod (122); The directions extending outward from the center point of the dielectric substrate I (11) are rod a, rod b, rod c, and rod d, respectively. The length of the rod (123) first increases and then decreases, and the longest rod d is located at the outermost side. Two energy-absorbing parts (13) are provided on each metal rod, wherein one energy-absorbing part (13) is located on the branch rod d, and the other energy-absorbing part (13) is located between the branch rod b and the branch rod c; The energy dissipation component (13) is arranged at the center of the branch rod (123), and the energy dissipation component (13) includes two metal patches (131) arranged opposite to each other and a resistor (132) located between the metal patches (131).

2. The tunable low-profile dual-polarization ATA absorbent metasurface according to claim 1, wherein: There are four metal rods.

3. The tunable low-profile dual-polarization ATA absorbent metasurface according to claim 1, wherein: The dielectric substrate I (11) in the absorbing screen unit is square with a side length of 8-12 mm, a thickness of 0.1-1 mm, a dielectric constant of 2.2-3.66, a thickness of the metal foil microunit (12) of 0.017-0.035 mm, a width of the metal wire (121) of 0.1-0.3 mm, and a distance between two parallel metal wires (121) of 0.2-0.5 mm.

4. The controllable low-profile dual-polarization ATA absorbent metasurface according to any one of claims 1 to 3, wherein: The wave-transmitting screen comprises a plurality of wave-transmitting screen units I (2) distributed in a periodic array, wherein the wave-transmitting screen unit I (2) comprises a dielectric substrate II (22) and a metal foil (21) attached to the upper surface of the dielectric substrate II (22), wherein the metal foil (21) is provided with a rectangular slit (211), and the dielectric substrate II (22) on the wave-transmitting screen unit I (2) and the dielectric substrate I (11) on the wave-absorbing screen unit (1) are bonded together.

5. The tunable low-profile dual-polarization ATA absorbent metasurface according to claim 4, wherein: The distance between the dielectric substrate II (22) on the wave-transmitting screen unit I (2) and the dielectric substrate I (11) on the wave-absorbing screen unit (1) is 1-4 mm.

6. The controllable low-profile dual-polarization ATA absorbent metasurface according to any one of claims 1 to 3, wherein: The wave-transmitting screen comprises a plurality of wave-transmitting screen units II (3) distributed in a periodic array, wherein the wave-transmitting screen unit II (3) comprises a lower metal foil micro-unit (31), a dielectric substrate III (32), a middle metal foil micro-unit (34), a dielectric substrate IV (35) and an upper metal foil micro-unit (36) which are stacked in sequence; The lower metal foil micro-unit (31) and the upper metal foil micro-unit (36) have the same structure, comprising a central metal foil (311) and a peripheral metal foil (312) that are not in contact with each other, two trapezoidal regions (313) symmetrically centered about the central metal foil (311) are etched on the peripheral metal foil (312), the trapezoidal regions (313) and the central metal foil (311) being in direct contact, and a variable capacitance diode (314) being connected between the peripheral metal foil (312) and the central metal foil (311) where the trapezoidal regions (313) are not etched. The trapezoidal regions of the lower metal foil micro-unit (31) and the upper metal foil micro-unit (36) do not overlap each other; The middle metal foil micro-unit (34) includes two intersecting metal lines (341), and the intersection point (342) of the metal lines (341) connects the lower metal foil micro-unit (31) and the upper metal foil micro-unit (36).

7. The tunable low-profile dual-polarization ATA absorbent metasurface according to claim 6, wherein: Two symmetrically arranged slits (3111) are etched on the central metal foil (311) and are located on the side of the varactor diode (314).

8. The tunable low-profile dual-polarization ATA absorbent metasurface according to claim 6, wherein: The short side of the trapezoidal region (313) is closer to the central metal foil (311) than the long side of the trapezoidal region (313), and further comprises an adhesive sheet (33) for bonding the dielectric substrate III (32) and the dielectric substrate IV (35).

9. A radome, characterized in that: It comprises the adjustable low-profile dual-polarization ATA absorbent metasurface as described in any one of claims 1-8.

Images