Frequency selection wave absorber structure and array thereof

Abstract

The invention discloses a frequency selection wave absorber structure and an array thereof, the frequency selection wave absorber structure comprises a lossy wave absorbing layer, a controllable lossy wave absorbing layer and a controllable lossless frequency selection layer which are arranged at intervals from top to bottom, the lossy wave absorbing layer comprises a first dielectric substrate, and the first dielectric substrate is provided with a first wave absorbing metal structure; the controllable lossy wave absorbing layer comprises a second dielectric substrate, and a second wave absorbing metal structure is arranged on the second dielectric substrate; a pair of longitudinal first pin diodes and a pair of transverse first pin diodes are arranged in the second metal structure; the controllable lossless frequency selection layer comprises a third dielectric substrate, and a square patch is arranged on the third dielectric substrate; a square ring gap is formed in the middle of the square patch, and a pair of longitudinal second pin diodes and a pair of transverse second pin diodes are arranged in the square ring gap; the controllable lossless frequency selection layer is matched with the controllable lossless wave absorbing layer, and the reconfigurable passband window and independent polarization selection are realized by controlling the first pin diode and the second pin diode.

Description

Technical Field

[0001] The present invention relates to the technical field of spatial filters, and particularly to a frequency selective absorber structure with a closable passband and polarization selectivity and its array. Background Art

[0002] Traditional radomes mostly adopt frequency selective surface design, which is a lossless resonant structure and can only reduce the radar cross section of single-static, and gradually cannot meet the requirements of radar stealth. In order to improve the stealth ability of radar systems, frequency selective absorber structures are proposed. The frequency selective absorber structure reduces the out-of-band radar cross section by absorbing out-of-band incident waves, and can also ensure the normal operation within the radar band. However, after the unit structure of the passive frequency selective surface is determined, its frequency selective characteristics are basically fixed and cannot adapt to the changing electromagnetic environment. Therefore, reconfigurable frequency selective surfaces emerge as the times require.

[0003] Currently, the closing of the transmission window of the frequency selective absorber is generally based on the state of the lossless frequency selective layer controlled by pin diodes, which shows the switching of the transmission window state between the two states of low insertion loss transmission and reflection. It can only achieve the attenuation of the out-of-band radar cross section. When the opponent's radar and our radar are in the same frequency band, the stealth effect will fail. In addition, the current reconfigurable state conversion is the simultaneous conversion of TE and TM polarizations, and the flexibility of reconfiguration is also limited. Therefore, it is very important and urgent to design a frequency selective absorber structure with a closable passband and polarization selectivity and its array. Summary of the Invention

[0004] The purpose of the present invention is to provide a frequency selective absorber structure and its array, which can achieve the effect of full-band stealth by closing the transmission window through pin diodes, and can achieve polarization selection through different states of the DC bias circuit.

[0005] To achieve the above task, the present invention adopts the following technical solutions:

[0006] A frequency selective absorber structure includes a lossy absorbing layer, a controllable lossy absorbing layer, and a controllable lossless frequency selective layer arranged at intervals from top to bottom, wherein:

[0007] The lossy absorbing layer includes a first dielectric substrate, and a first absorbing metal structure is arranged on the first dielectric substrate;

[0008] The controllable lossy absorbing layer includes a second dielectric substrate, and a second absorbing metal structure is arranged on the second dielectric substrate; A pair of longitudinal first pin diodes and a pair of transverse first pin diodes are arranged in the second metal structure;

[0009] The controllable lossless frequency selective layer includes a third dielectric substrate, on which a square patch is disposed; a square loop slot is arranged in the middle of the square patch, and a pair of longitudinal second pin diodes and a pair of transverse second pin diodes are arranged in the square loop slot;

[0010] The controllable lossless frequency selective layer cooperates with the controllable lossy absorbing layer, and realizes the reconfigurability of the passband window and the polarization-independent selection by controlling the first pin diodes and the second pin diodes.

[0011] Further, the first absorbing metal structure includes a first circular metal patch, and first T-shaped metal strips are evenly distributed around the first circular metal patch; wherein, a first annular slot is arranged inside the first circular metal patch, and a plurality of first strip-shaped slots are spaced apart in the direction towards the center of the first circular metal patch along the inner side of the first annular slot; a first resistor is loaded on the first T-shaped metal strip near the connection with the first circular metal patch.

[0012] Further, the first T-shaped metal strips are evenly distributed around the first circular metal patch at intervals of 90°. Inside the annular slot of the first circular metal patch, with the direction passing through the center and defined as 0° horizontally, the first strip-shaped slots are respectively opened in the directions of ±25°, ±45°, ±65°, ±115°, ±135° and ±155°.

[0013] Further, the second absorbing metal structure includes a second circular metal patch, and second T-shaped metal strips are evenly distributed around the second circular metal patch; wherein, a second annular slot is arranged inside the second circular metal patch, and a plurality of second strip-shaped slots are spaced apart in the direction towards the center of the second circular metal patch along the inner side of the second annular slot; a second resistor is loaded on the second T-shaped metal strip near the connection with the second circular metal patch;

[0014] A pair of longitudinal first pin diodes and a pair of transverse first pin diodes are distributed on the second annular slot and are respectively used to control electromagnetic waves of TE and TM polarizations, so as to realize the switching of the control transmission and absorption states. A plurality of DC blocking capacitors are arranged between the second annular slot and the edge of the second circular metal patch to separate the DC biases of TE and TM polarizations, so as to realize independent control of TE and TM polarized waves.

[0015] Further, the distance between the second strip-shaped slot and the center of the second circular metal patch is less than the distance between the end of the first strip-shaped slot and the center of the first circular metal patch.

[0016] Further, the adjacent first pin diodes are spaced 90° apart, and the directions of the first pin diodes in the longitudinal and transverse directions are each kept consistent; four DC-blocking capacitors are provided, respectively located between the adjacent first pin diodes.

[0017] Further, each side of the square loop slot has a concave structure; among them, a pair of longitudinal second pin diodes are provided in a pair of longitudinal concave structures, and a pair of transverse second pin diodes are provided in a pair of transverse concave structures;

[0018] Isolation slots extending to the corresponding corners of the third dielectric substrate are opened at each corner of the square loop slot, and a DC-blocking capacitor is provided in each isolation slot to separate the DC bias circuits of TE and TM polarizations.

[0019] Further, when all the first pin diodes and all the second pin diodes on the lossless frequency selective layer and the controllable lossy absorbing layer are all turned on, it shows dual-polarization full-band absorption; when all are turned off, there is a low insertion loss transmission window for both dual-polarization TE / TM;

[0020] When a pair of longitudinal first pin diodes on the lossless frequency selective layer and a corresponding pair of longitudinal second pin diodes in the controllable lossy absorbing layer are turned on, it shows TE full-band absorption and there is a low insertion loss transmission window for TM;

[0021] When a pair of transverse first pin diodes on the lossless frequency selective layer and a corresponding pair of transverse second pin diodes in the controllable lossy absorbing layer are turned on, it shows TM full-band absorption and there is a low insertion loss transmission window for TE.

[0022] A frequency selective absorber array is formed by arranging the frequency selective absorber structures in an array.

[0023] A radar system employs the frequency selective absorber array.

[0024] Compared with the prior art, the present invention has the following technical features:

[0025] Based on pin diodes, the present invention realizes the design of a frequency selective absorber with a closable passband, which can realize the reconfigurable closing of the transmission window and then achieve full-band absorption, realizing radar stealth within the full band. In addition, the integrated design of the DC feeding line and the frequency selective structure greatly reduces the influence of the extra feeding line on the high-frequency performance; by loading isolation capacitors to separate the DC bias circuits of TE and TM polarizations, the polarization-independent and flexible control can be achieved. Description of the Drawings

[0026] Figure 1Schematic diagram of the frequency selective absorber structure of the present invention;

[0027] Figure 2 Structural diagram of the lossy absorbing layer in the present invention;

[0028] Figure 3 Structural diagram of the controllable lossy absorbing layer in the present invention;

[0029] Figure 4 Structural diagram of the controllable lossless frequency selective layer in the present invention;

[0030] Figure 5 Structural diagram of the frequency selective absorber array in the present invention;

[0031] Figure 6 (a), (b), (c), and (d) are S-parameter diagrams under different states at normal incidence in an embodiment of the present invention. Detailed implementation manners

[0032] Refer to the appendix Figure 1 , the present invention provides a frequency selective absorber structure, which can flexibly switch the transmission window state of the frequency selective absorber between low insertion loss wave transmission and high-efficiency absorption in different polarization states, and can realize the selection of different polarizations according to different states of the control circuit; the absorber structure includes a lossy absorbing layer 1, a controllable lossy absorbing layer 2, and a controllable lossless frequency selective layer 3 which are spaced apart by an air layer from top to bottom, wherein:

[0033] 1. Lossy absorbing layer.

[0034] The lossy absorbing layer 1 includes a first dielectric substrate 11, and a first absorbing metal structure is arranged on the first dielectric substrate 11; the first absorbing metal structure includes a first circular metal patch 13, and first T-shaped metal strips 12 are evenly distributed around the first circular metal patch 13; wherein, a first annular gap is arranged inside the first circular metal patch 13, and multiple first strip-shaped grooves are spaced apart along the direction towards the center of the first circular metal patch 13 on the inner side of the first annular gap; a first resistor 1-1 is loaded on the first T-shaped metal strip 12 near the connection with the first circular metal patch 13 to loss electromagnetic waves.

[0035] As Figure 2As shown, in an embodiment of the present invention, the first dielectric substrate 11 has a square structure, and the side length P of the first dielectric substrate 11 is 18 mm; the first T-shaped metal strips 12 are evenly distributed around the first circular metal patch 13 at intervals of 90°, and the overall length L1 between the first T-shaped metal strips 12 that are opposite to each other at an interval of 180° is 17.9 mm; the first T-shaped metal strip 12 includes a metal strip located at the edge of the first dielectric substrate 11 and a metal strip connected to the first circular metal patch 13, where the width of the metal strip located at the edge of the first dielectric substrate 11 is W1 = 0.5 mm and the length L s2 = 5 mm; the width of the metal strip connected to the first circular metal patch 13 is W2 = 0.8 mm; and a first resistor 1-1 is loaded on this metal strip to attenuate electromagnetic waves. Inside the annular gap of the first circular metal patch 13, with the direction passing through the center of the circle and defined as 0° horizontally, then first strip-shaped slots with a width of W3 = 0.2 mm are respectively opened in the directions of ±25°, ±45°, ±65°, ±115°, ±135° and ±155°; the distance R 14 between the end of the first strip-shaped slot and the center of the first circular metal patch 13 is 2.1 mm, the distance R3 between the inner side of the first annular gap and the center of the first circular metal patch 13 is 4.4 mm, the distance R2 between the outer side of the first annular gap and the center of the circular metal patch 13 is 4.5 mm, and the radius R1 of the first circular metal patch 13 is 5 mm.

[0036] 2. Controllable lossy absorbing layer.

[0037] The controllable lossy absorbing layer 2 includes a second dielectric substrate 21, and a second absorbing metal structure is disposed on the second dielectric substrate 21; the second absorbing metal structure includes a second circular metal patch 23, and second T-shaped metal strips 22 are uniformly distributed around the second circular metal patch 23; wherein, a second annular slot is disposed inside the second circular metal patch 23, and a plurality of second strip-shaped slots are spaced apart along the direction towards the center of the second circular metal patch 23 on the inner side of the second annular slot; the distance between the second strip-shaped slot and the center of the second circular metal patch 23 is less than the distance between the end of the first strip-shaped slot and the center of the first circular metal patch 13; a second resistor 2-1 is loaded on the second T-shaped metal strip 22 near the connection with the second circular metal patch 13 to dissipate electromagnetic waves; a pair of longitudinal first pin diodes 2-2 and a pair of transverse first pin diodes 2-2 are distributed on the second annular slot and are respectively used to control electromagnetic waves of TE and TM polarizations, so as to realize the switching between the control transmission and absorbing states. The adjacent first pin diodes 2-2 are spaced 90° apart, and the directions of the longitudinal and transverse first pin diodes 2-2 are each kept consistent; a plurality of DC blocking capacitors 2-3 are disposed between the edge of the second annular slot and the second circular metal patch 23 to separate the DC biases of TE and TM polarizations, so as to independently control TE and TM polarized waves, improve the flexibility of control and realize polarization independent control; wherein, four DC blocking capacitors 2-3 are disposed, and are respectively located between the adjacent first pin diodes 2-2. In the present invention, TE polarization represents a uniform plane wave with the electric field direction being longitudinal, and TM polarization represents a uniform plane wave with the electric field direction being transverse.

[0038] In an embodiment of the present invention, the second dielectric substrate 21 is a square structure with a side length P = 18 mm; the second T-shaped metal strips 22 are uniformly distributed around the second circular metal patch 23 at intervals of 90°; wherein the overall length between the second T-shaped metal strips 22 opposite to each other at an interval of 180° is L1 = 17.9 mm; the second T-shaped metal strip 22 includes a metal strip at the edge of the second dielectric substrate 21 and a metal strip connected to the second circular metal patch 23. The width of the metal strip at the edge of the second dielectric substrate 21 is W1 = 0.5 mm, and the length L s2 = 5 mm; the width of the metal strip connected to the second circular metal patch 23 is W2 = 0.8 mm; and a second resistor 2-1 is loaded on the metal strip to dissipate electromagnetic waves; on the inner side of the annular slot of the second circular metal patch 23, taking the direction passing through the center and defining the transverse direction as 0°, second strip-shaped slots with a width of W3 = 0.2 mm are respectively opened in the directions of ±25°, ±45°, ±65°, ±115°, ±135° and ±155°; the distance R between the end of the second strip-shaped slot and the center of the second circular metal patch 23 24= 2.4 mm, the distance R3 between the inner side of the second annular gap and the center of the second circular metal patch 23 is 4.4 mm, the distance R2 between the outer side of the second annular gap and the center of the second circular metal patch 23 is 4.5 mm, and the radius R1 of the second circular metal patch 23 is 5 mm.

[0039] 3. Controllable lossless frequency selective layer.

[0040] The controllable lossless frequency selective layer 3 includes a third dielectric substrate 31, and a square patch 32 is arranged on the third dielectric substrate; a square ring gap is arranged in the middle of the square patch 32, and each side of the square ring gap has a concave structure; among them, a pair of longitudinal second pin diodes 3-2 are arranged in a pair of longitudinal concave structures, and a pair of transverse second pin diodes 3-2 are arranged in a pair of transverse concave structures, which are respectively used to control electromagnetic waves of TE and TM polarizations, and the directions of the longitudinal and transverse second pin diodes 3-2 are kept consistent; isolation grooves (on the diagonal of the third dielectric substrate 31) extending to the corresponding corners of the third dielectric substrate 31 are opened at each corner of the square ring gap, and a blocking capacitor 3-1 is arranged in each isolation groove to separate the DC bias circuits of TE and TM polarizations, so that it has polarization selectivity and thus improves the flexibility of control.

[0041] In one embodiment of the present invention, as Figure 4 shown, the third dielectric substrate 31 is a square structure with a side length of P = 18 mm; the outer side length of the square ring gap is L 31 = 7 mm, and the inner side length is L 32 = 6.6 mm; the outer width W 31 of the concave structure is 2 mm, and the inner width is W 31 = 1.6 mm; the distances between a pair of transverse concave structures and a pair of longitudinal concave structures are both L 33 = 4 mm; the width of the isolation groove is W 3g = 0.1 mm.

[0042] 4. Application of the absorber structure.

[0043] The controllable lossless frequency selective layer 2 and the controllable lossy absorber layer 3 cooperate. By controlling the first pin diode 2-2 and the second pin diode 3-2, reconfigurable passband windows and polarization-independent selection can be achieved; the passband window of the lossy absorber layer 1 is fixed and uncontrollable, and it is placed on the top to expand the absorption bandwidth.

[0044] The absorber structure has a total of four working states:

[0045] When all the first PIN diodes 2-2 and all the second PIN diodes 3-2 on the lossless frequency selective layer 2 and the controllable lossy absorbing layer 3 are fully turned on, it shows dual-polarization full-band absorption; when all are turned off, there is a low insertion loss transmission window for both dual-polarization TE / TM.

[0046] When a pair of longitudinal first PIN diodes 2-2 on the lossless frequency selective layer 2 and a corresponding pair of longitudinal second PIN diodes 3-2 in the controllable lossy absorbing layer 3 are turned on, it shows TE full-band absorption and there is a low insertion loss transmission window for TM.

[0047] When a pair of transverse first PIN diodes 2-2 on the lossless frequency selective layer 2 and a corresponding pair of transverse second PIN diodes 3-2 in the controllable lossy absorbing layer 3 are turned on, it shows TM full-band absorption and there is a low insertion loss transmission window for TE.

[0048] As Figure 5 shown, the present invention also provides a frequency selective absorber array, which is formed by arranging the frequency selective absorber structures in an array.

[0049] The present invention integrates the DC feeding line with the frequency selective structure, greatly reducing the influence of the additional DC feeding on the high-frequency performance and achieving bias control without affecting the frequency characteristics. In addition, the present invention separates the DC bias circuits of TE and TM polarized electromagnetic waves by loading DC-blocking capacitors, and can realize independent, flexible and controllable of different polarized waves.

[0050] In an embodiment of the present invention, the air layer height H1 between the lossy absorbing layer 1 and the controllable lossy absorbing layer 2 is 3.5 mm, and the air layer height H2 between the controllable lossy absorbing layer 2 and the controllable lossless frequency selective layer 3 is 9.5 mm; the thickness of the first dielectric substrate 11, the thickness h m1 = h m2 = 0.5 mm, and the thickness of the third dielectric substrate 31 is h m3 = 0.254 mm; all three dielectric substrates are made of Rogers 4350B material with a dielectric constant of 3.65 and a loss tangent of 0.0037.

[0051] The S parameters of the invented frequency selective absorber structure are as Figure 6 shown; the frequency range where S11 is less than -9 dB is 2.3 - 8.4 GHz, the passband is at 6.9 GHz, and its insertion loss is 0.65 dB. The -3 dB bandwidth is 5.75 - 6.2 GHz; as Figure 6 (a) shown, when eight PIN diodes in the longitudinal and transverse directions are all cut off, both TE and TM polarized waves generate a transmission window at 6.9 GHz with an insertion loss of 0.65 dB; asFigure 6 As shown in (b) of , when the four PIN diodes in the longitudinal direction are cut off and the four PIN diodes in the transverse direction are turned on, the wave absorption rate of TM polarization is greater than 85% in the range of 2.3 - 8.4 GHz, and a transmission window with an insertion loss of 0.65 dB is generated at 6.9 GHz for TE polarization; as Figure 6 As shown in (c) of , when the four PIN diodes in the longitudinal direction are turned on and the four PIN diodes in the transverse direction are cut off, a transmission window with an insertion loss of 0.65 dB is generated at 6.9 GHz for TM polarization, and the wave absorption rate of TE polarization is greater than 85% in the range of 2.3 - 8.4 GHz; as Figure 6 As shown in (d) of , when all eight PIN diodes (2 - 2, 3 - 2) in the longitudinal and transverse directions are turned on, the wave absorption rates of both TE and TM polarizations are greater than 85% in the range of 2.3 - 8.4 GHz. The state control is shown in Table 1.

[0052] Table 1 State control table in the embodiment

[0053] State 1 State 2 State 3 State 4 Controllable lossy absorbing layer (longitudinal PIN diode) Cut-off Cut-off Conduction Conduction Controllable lossy absorbing layer (transverse PIN diode) Cut-off Conduction Cut-off Conduction Controllable lossless frequency selective layer (longitudinal PIN diode) Cut-off Cut-off Conduction Conduction Controllable lossless frequency selective layer (transverse PIN diode) Cut-off Conduction Cut-off Conduction TE polarized wave A-T-A A-T-A A-A-A A-A-A TM polarized wave A-T-A A-A-A A-T-A A-A-A

[0054] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A frequency selective absorber structure, characterized in that: The invention comprises a lossy absorbing layer (1), a controllable lossy absorbing layer (2) and a controllable lossless frequency selective layer (3) which are arranged in intervals from top to bottom, wherein: The lossy absorbing layer (1) comprises a first dielectric substrate (11), on which a first absorbing metal structure is arranged; The controllable lossy absorbing layer (2) comprises a second dielectric substrate (21), on which a second absorbing metal structure is arranged; a pair of longitudinal first pin diodes (2-2) and a pair of transverse first pin diodes (2-2) are arranged in the second metal structure; The controllable lossless frequency selection layer (3) comprises a third dielectric substrate (31), on which a square patch (32) is arranged; a square ring gap is arranged in the middle of the square patch (32), and a pair of longitudinal second pin diodes (3-2) and a pair of transverse second pin diodes (3-2) are arranged in the square ring gap; The controllable lossless frequency selection layer (2) cooperates with the controllable lossy absorbing layer (3) to achieve reconfigurable passband window and polarization independent selection by controlling the first pin diode (2-2) and the second pin diode (3-2).

2. The frequency selective absorber structure according to claim 1, characterized in that: The first wave-absorbing metal structure comprises a first circular metal patch (13), and first T-shaped metal strips (12) are evenly distributed around the first circular metal patch (13); wherein a first annular gap is provided inside the first circular metal patch (13), and a plurality of first strip grooves are distributed at intervals inside the first annular gap in a direction toward the center of the first circular metal patch (13); and a first resistor (1-1) is loaded on the first T-shaped metal strip (12) near the connection with the first circular metal patch (13).

3. The frequency selective absorber structure according to claim 1, characterized in that: The first T-shaped metal strips (12) are evenly distributed around the first circular metal patch (13) at intervals of 90°, and the first strip grooves are respectively opened in the inner side of the annular gap of the first circular metal patch (13), passing through the center of the circle and with 0° defined in the horizontal direction, in the directions of ±225°, ±245°, ±65°, ±115°, ±135° and ±155°.

4. The frequency selective absorber structure according to claim 1, characterized in that: The second wave-absorbing metal structure comprises a second circular metal patch (23), and second T-shaped metal strips (22) are evenly distributed around the second circular metal patch (23); wherein a second annular gap is provided inside the second circular metal patch (23), and a plurality of second strip grooves are distributed at intervals inside the second annular gap in a direction toward the center of the second circular metal patch (23); and a second resistor (2-1) is loaded on the second T-shaped metal strip (22) near the connection with the second circular metal patch (13); A pair of longitudinal first pin diodes (2-2) and a pair of transverse first pin diodes (2-2) are distributed on the second annular gap, respectively used to control electromagnetic waves of TE and TM polarizations, so as to realize the switching of control transmission and wave absorption states. A plurality of DC blocking capacitors (2-3) are arranged between the second annular gap and the edge of the second circular metal patch (23) to separate the DC bias of TE and TM polarizations, thereby realizing independent control of TE and TM polarized waves.

5. The frequency selective absorber structure according to claim 4, characterized in that: The distance between the second strip-shaped groove and the center of the second circular metal patch (23) is smaller than the distance between the end of the first strip-shaped groove and the center of the first circular metal patch (13).

6. The frequency selective absorber structure according to claim 4, characterized in that: Adjacent first pin diodes (2-2) are spaced 90 degrees apart, and the longitudinal and transverse directions of the first pin diodes (2-2) remain consistent; four DC blocking capacitors (2-3) are provided, and are respectively located between adjacent first pin diodes (2-2).

7. The frequency selective absorber structure according to claim 1, characterized in that: Each side of the square ring gap has a concave structure; a pair of longitudinal second PIN diodes (3-2) are arranged in a pair of longitudinal concave structures, and a pair of transverse second PIN diodes (3-2) are arranged in a pair of transverse concave structures; An isolation slot extending to a corresponding corner of a third dielectric substrate (31) is provided at each corner of the square ring gap, and a DC isolation capacitor (3-1) is provided in each isolation slot to separate TE and TM polarized DC bias circuits.

8. The frequency selective absorber structure according to claim 1, characterized in that: When all first pin diodes (2-2) and all second pin diodes (3-2) on the lossless frequency selective layer (2) and the controllable lossy absorbing layer (3) are fully turned on, dual-polarization full-band absorbing is achieved; when all are turned off, dual-polarization TE / TM both have a low insertion loss transmission window; When a pair of first longitudinal pin diodes (2-2) on the lossless frequency selective layer (2) and a corresponding pair of second longitudinal pin diodes (3-2) in the controllable lossy absorbing layer (3) are turned on, TE full-band absorbing is performed, and TM has a low insertion loss transmission window; When a pair of first lateral pin diodes (2-2) on the lossless frequency selection layer (2) and a corresponding pair of second lateral pin diodes (3-2) in the controllable lossy absorbing layer (3) are turned on, TM full-band absorbing is exhibited, and TE has a low insertion loss transmission window.

9. A frequency selective absorber array, characterized in that: The array is composed of the frequency selective absorber structures according to any one of claims 1 to 8 arranged in an array.

10. A radar system, characterized in that: The system adopts the frequency selective absorber array according to claim 9.

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