Multifunctional active wave absorber with reflection polarization conversion in high frequency band

Abstract

The application provides a multifunctional active wave absorber with reflection polarization conversion in a high frequency band, comprising a plurality of active wave absorber units arranged periodically, each active wave absorber unit comprising a top polarization converter, a loss layer, a switching layer and a bias circuit layer; the top polarization conversion layer comprises a double "C" type metal patch and a first dielectric layer; the loss layer comprises a plurality of symmetrical resistors, metal patches and a second dielectric layer; the switching layer comprises a plurality of symmetrical PIN diodes and metal patches; the bias circuit comprises a third dielectric layer, a metal microstrip line and a metallized via group. By controlling the on-off of the PIN diodes, the wave absorption-transmission-polarization conversion or wave absorption-reflection-polarization conversion function can be realized. The application can provide stable dual polarization characteristics, realize switching of the working state by controlling the on-off of the PIN diodes, effectively reduce the backscattering of a single station radar, has the characteristics of multifunction, dual polarization and the like, and has a wide application prospect in radar stealth technology.

Description

Technical fields:

[0001] This invention belongs to the field of electromagnetic protection technology, specifically relating to a multifunctional active absorber with reflective polarization conversion in the high-frequency band. Background technology:

[0002] With the rapid development of electromagnetic detection technology, the risk of antenna systems being detected is increasing, making the research on radar stealth technology and radomes particularly important. Frequency-selective absorbers, when applied to stealth radomes, can absorb out-of-band incident waves while ensuring low transmission band insertion loss, thereby greatly reducing monostatic and bistatic radar cross-sections (RCS) and achieving stealth functionality.

[0003] Frequency-selective absorbers are commonly classified into three types based on the relative positions of the transmission and absorption bands: 1) the passband is to the left of the absorption band; 2) the passband is to the right of the absorption band; and 3) the passband is between the two absorption bands. However, current research mostly focuses on passive absorbers, which suffer from limited functionality. By loading PIN diodes onto frequency-selective absorbers, different electromagnetic characteristics can be achieved by changing the on / off state of the PIN diodes, thus enabling switching between different functions. PIN diodes, as a commonly used electromagnetic switch, have advantages such as small size, fast response speed, and low cost.

[0004] To date, numerous researchers have proposed active microwave absorber structures; however, most of them suffer from drawbacks such as limited functionality and polarization sensitivity. Therefore, designing a multifunctional active microwave absorber has significant application value and importance in the fields of electromagnetic protection and stealth. Summary of the Invention:

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a multifunctional active absorber with reflective polarization conversion in the high-frequency band. It employs a geometrically symmetrical structure design, offering different function switching and dual-polarization characteristics. Furthermore, by controlling the on / off state of the PIN diode, it can achieve absorption-transmission-polarization conversion and absorption-reflection-polarization function conversion. It possesses multifunctional and dual-polarization characteristics, has a simple manufacturing process, and shows significant application potential in electromagnetic protection equipment. It effectively solves the problems of limited functional design and polarization sensitivity in existing structures.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] This invention provides a multifunctional active absorber with high-frequency reflective polarization conversion, comprising a plurality of periodically arranged active absorber units. Each active absorber unit includes, from top to bottom, a top polarization converter, a loss layer, a switching layer, and a bias circuit layer. The top polarization converter includes symmetrically arranged first and second metal patches. The loss layer includes a third, a fourth, a first arrow-shaped metal patch, a second arrow-shaped metal patch, a third arrow-shaped metal patch, and a fourth arrow-shaped metal patch. The fourth metal patch is distributed outside the third metal patch, and the tail ends of the four sets of arrow-shaped metal patches are respectively connected to the four sides of the fourth metal patch. A first resistor, a second resistor, a third resistor, and a fourth resistor are respectively connected to the four sets of arrow-shaped metal patches. The switching layer includes a thirteenth and a fourteenth metal patch. The fourteenth metal patch is distributed outside the thirteenth metal patch; a first PIN diode, a second PIN diode, a third PIN diode, and a fourth PIN diode are connected between the thirteenth and fourteenth metal patches; the first PIN diode and a first resistor are connected in parallel between the first and second metal patches, the second PIN diode and a second resistor are connected in parallel between the second and third metal patches, the third PIN diode and a third resistor are connected in parallel between the third and fourth metal patches, and the fourth PIN diode and a fourth resistor are connected in parallel between the fourth metal patch and the first metal patch; the fourteenth metal patch and the bias circuit layer provide bias voltage for the PIN diodes, control the on / off state of the four sets of PIN diodes, and realize the absorption-transmission-polarization conversion function or the absorption-reflection-polarization conversion function.

[0008] Furthermore, the top-level polarization converter also includes a first dielectric substrate, with the first metal patch and the second metal patch disposed on the first dielectric substrate; the loss layer also includes a second dielectric substrate, with the third metal patch, the fourth metal patch, the first arrow-shaped metal patch, the second arrow-shaped metal patch, the third arrow-shaped metal patch, and the fourth arrow-shaped metal patch disposed on the second dielectric substrate.

[0009] Furthermore, the first metal patch and the second metal patch are double "C" shaped metal patches, symmetrically distributed; the first metal patch and the second metal patch are located at the center of the first dielectric substrate, and the axis of symmetry of the first metal patch and the second metal patch coincide with the diagonal of the first dielectric substrate.

[0010] Furthermore, the third metal patch has a square structure and is distributed at the center of the loss layer; the fourth metal patch has a square ring structure and is distributed outside the third metal patch, with the center point of the fourth metal patch coinciding with the center point of the third metal patch; the first arrow-shaped metal patch includes a fifth metal patch and a ninth metal patch, the second arrow-shaped metal patch includes a sixth metal patch and a tenth metal patch, the third arrow-shaped metal patch includes a seventh metal patch and an eleventh metal patch, and the fourth arrow-shaped metal patch includes an eighth metal patch and a twelfth metal patch; the fifth metal patch, the sixth metal patch, the seventh metal patch, and the eighth metal patch... Each of the metal patches is a rectangular metal strip, with one end connected to the center point of each of the four sides of the fourth metal patch; the ninth, tenth, eleventh, and twelfth metal patches are all equilateral "L"-shaped metal strips, respectively disposed at the other end of the fifth, sixth, seventh, and eighth metal patches, forming an arrowhead structure; the first, second, third, and fourth resistors are respectively connected to the fifth, sixth, seventh, and eighth metal patches; the fifth, sixth, seventh, and eighth metal patches coincide with the diagonal of the second dielectric substrate.

[0011] Furthermore, the thirteenth metal patch has a square structure and is distributed in the center of the switching layer, while the fourteenth metal patch has a square ring structure and is distributed outside the thirteenth metal patch, with the center point of the fourteenth metal patch coinciding with the center point of the thirteenth metal patch.

[0012] Furthermore, the bias circuit layer includes a third dielectric layer, metallized vias, and a metal microstrip line; the metal microstrip line is disposed on the third dielectric layer, and the metallized via is disposed at the center of the third dielectric layer.

[0013] Furthermore, the metal microstrip line passes through the metallized via; the metal microstrip line is electrically connected to the thirteenth metal patch through the metallized via, providing bias voltage for the first PIN diode, the second PIN diode, the third PIN diode, and the fourth PIN diode.

[0014] Furthermore, the switching layer achieves two independently switchable combinations of absorption-transmission-polarization conversion and absorption-reflection-polarization conversion by switching the first PIN diode, the second PIN diode, the third PIN diode, and the fourth PIN diode. Specifically:

[0015] When the first PIN diode, the second PIN diode, the third PIN diode, and the fourth PIN diode are all turned on, the multifunctional active absorber with reflective polarization conversion in the high-frequency band can realize the absorption-transmission-polarization conversion function in the low-frequency, mid-frequency, and high-frequency bands.

[0016] When the first PIN diode, the second PIN diode, the third PIN diode, and the fourth PIN diode are all disconnected, the multifunctional active absorber with high-frequency reflective polarization conversion can achieve absorption-reflection-polarization conversion functions in the low-frequency, mid-frequency, and high-frequency bands.

[0017] Furthermore, the active absorber comprises M×N periodically arranged active absorber units, where M≥2 and N≥2.

[0018] The beneficial effects of this invention are:

[0019] (1) In the structure of this invention, the top polarization converter, loss layer and switching layer are all symmetrical geometric structures, which can provide relatively stable dual polarization characteristics;

[0020] (2) The present invention controls the on / off state of four sets of PIN diodes through a switching layer and a bias circuit layer respectively, thereby achieving independent and controllable performance;

[0021] (3) The present invention can achieve two independent and switchable working states in the low frequency, medium frequency and high frequency bands: absorption-transmission-polarization conversion and absorption-reflection-polarization conversion. Attached image description:

[0022] Figure 1 This is a schematic diagram of the unit structure of a multifunctional active absorber with high-frequency reflective polarization conversion according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the top polarization conversion layer of a multifunctional active absorber with reflective polarization conversion in the high-frequency band, according to an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the loss layer of a multifunctional active absorber with reflective polarization conversion in the high-frequency band, according to an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the switching layer of a multifunctional active absorber with reflective polarization conversion in the high-frequency band, according to an embodiment of the present invention.

[0026] Figure 5 This is a side view of the unit structure layer of a multifunctional active absorber with reflective polarization conversion in the high-frequency band according to an embodiment of the present invention.

[0027] Figure 6 (a) is a graph showing the reflection coefficient (S11) and transmission coefficient (S21) of TE and TM polarization when the diode is turned on in an embodiment of the present invention.

[0028] Figure 6(b) is a graph showing the reflection coefficient (S11) and transmission coefficient (S21) of TE and TM polarization when the diode is off, according to an embodiment of the present invention.

[0029] The labels in the attached diagram are:

[0030] P1, First metal patch; P2, Second metal patch; P3, Third metal patch; P4, Fourth metal patch; P5, Fifth metal patch; P6, Sixth metal patch; P7, Seventh metal patch; P8, Eighth metal patch; P9, Ninth metal patch; P10, Tenth metal patch; P11, Eleventh metal patch; P12, Twelfth metal patch; P13, Thirteenth metal patch; P14, Fourteenth metal patch; D1, First PIN diode; D2, Second PIN diode; D3, Third PIN diode; D4, Fourth PIN diode; R1, First resistor; R2, Second resistor; R3, Third resistor; R4, Fourth resistor; T1, First dielectric substrate; T2, Second dielectric substrate; T3, Third dielectric substrate; S, Metal microstrip line; h, Metallized via. Detailed implementation method:

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] Reference Figures 1-5 This embodiment provides a multifunctional active absorber with high-frequency reflective polarization conversion, comprising M×N periodically arranged active absorber units, where M≥2 and N≥2.

[0034] Each active absorber unit includes a top-level polarization converter, a loss layer, a switching layer, and a bias circuit layer, distributed from top to bottom.

[0035] In this embodiment, the top-level polarization converter includes a first dielectric substrate T1 and a first metal patch P1 and a second metal patch P2 symmetrically disposed on the first dielectric substrate T1. The first metal patch P1 and the second metal patch P2 are double "C" shaped metal patches, symmetrically distributed, and the first metal patch P1 and the second metal patch P2 are distributed in the central part of the first dielectric substrate T1. The axis of symmetry of the first metal patch P1 and the second metal patch P2 coincides with the diagonal of the first dielectric substrate T1.

[0036] In this embodiment, the loss layer includes a second dielectric substrate T2, on which are disposed a third metal patch P3, a fourth metal patch P4, a first arrow-shaped metal patch, a second arrow-shaped metal patch, a third arrow-shaped metal patch, and a fourth arrow-shaped metal patch. The third metal patch P3 has a square structure and is located at the center of the loss layer. The fourth metal patch P4 has a square ring structure and is located outside the third metal patch P3, with its center point coinciding with the center point of the third metal patch P3. The first arrow-shaped metal patch includes a fifth metal patch P5 and a ninth metal patch P9; the second arrow-shaped metal patch includes a sixth metal patch P6 and a tenth metal patch P10; the third arrow-shaped metal patch includes a seventh metal patch P7 and an eleventh metal patch P11; and the fourth arrow-shaped metal patch includes an eighth metal patch. The fourth metal plate consists of two metal patches: the fifth metal patch P8 and the twelfth metal patch P12. The fifth, sixth, seventh, and eighth metal patches P5, P6, P7, and P8 are all rectangular metal strips, with one end perpendicularly connected to the center points of the four sides of the fourth metal patch P4. The ninth, tenth, eleventh, and twelfth metal patches P9, P10, P11, and P12 are all equilateral "L"-shaped metal strips, respectively positioned at the other ends of the fifth, sixth, seventh, and eighth metal patches P5, forming an arrowhead structure. A first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4 are respectively placed on the fifth, sixth, seventh, and eighth metal patches P5. The fifth, sixth, seventh, and eighth metal patches P5 coincide with the diagonal of the second dielectric substrate T2.

[0037] In this embodiment, the switching layer includes a thirteenth metal patch P13 and a fourteenth metal patch P14. The thirteenth metal patch P13 has a square structure and is located at the center of the switching layer. The fourteenth metal patch P14 has a square ring structure and is located outside the thirteenth metal patch P13, with the center point of the fourteenth metal patch P14 coinciding with the center point of the thirteenth metal patch P13. A first PIN diode D1, a second PIN diode D2, a third PIN diode D3, and a fourth PIN diode D4 are connected between the thirteenth metal patch P13 and the fourteenth metal patch P14. The first PIN diode D1, the second PIN diode D2, the third PIN diode D3, and the fourth PIN diode D4 are respectively connected to the center of the four sides of the thirteenth metal patch P13 and the fourteenth metal patch P14. Furthermore, the negative terminals of the first PIN diode D1, the second PIN diode D2, the third PIN diode D3, and the fourth PIN diode D4 are connected to the thirteenth metal patch P13, and the positive terminals are connected to the fourteenth metal patch P14.

[0038] In this embodiment, the bias circuit layer includes a third dielectric layer T3, a metallized via h, and a metal microstrip line S. The metal microstrip line S is disposed on the third dielectric layer T3, and the metallized via h is disposed at the center of the third dielectric layer T3. The metal microstrip line S passes through the metallized via h and is electrically connected to the thirteenth metal patch P13 through the metallized via h, providing bias voltage for the first PIN diode D1, the second PIN diode D2, the third PIN diode D3, and the fourth PIN diode D4.

[0039] In this embodiment, the first PIN diode D1 and the first resistor R1 are connected in parallel between the first metal patch P1 and the second metal patch P2; the second PIN diode D2 and the second resistor R2 are connected in parallel between the second metal patch P2 and the third metal patch P3; the third PIN diode D3 and the third resistor R3 are connected in parallel between the third metal patch P3 and the fourth metal patch P4; and the fourth PIN diode D4 and the fourth resistor R4 are connected in parallel between the fourth metal patch P4 and the first metal patch P1.

[0040] In this embodiment, the fourteenth metal patch P14 of the switching layer and the bias circuit layer provide bias voltage for the PIN diodes and control the on / off state of the four sets of PIN diodes. The switching layer realizes two independent and switchable combination states of absorption-transmission-polarization conversion and absorption-reflection-polarization conversion through the on / off state of the first PIN diode D1, the second PIN diode D2, the third PIN diode D3 and the fourth PIN diode D4, thereby realizing the absorption-transmission-polarization conversion function or the absorption-reflection-polarization conversion function.

[0041] Specifically: When all four PIN diodes—D1, D2, D3, and D4—are conducting, the multifunctional active absorber with high-frequency reflective polarization conversion can achieve absorption-transmission-polarization conversion in the low, mid, and high frequency bands; when all four PIN diodes—D1, D2, D3, and D4—are de-converted, the multifunctional active absorber with high-frequency reflective polarization conversion can achieve absorption-reflection-polarization conversion in the low, mid, and high frequency bands.

[0042] Example 2

[0043] Reference Figures 1-5 This embodiment provides a multifunctional active absorber with high-frequency reflective polarization conversion. Its overall structure is the same as that of the embodiment, except that the embodiment specifically defines the specifications of each metal patch, PIN diode of the dielectric layer, and resistor in embodiment 1.

[0044] In this embodiment, the first dielectric layer is a cube with a side length p of 16 mm and a thickness h1 of 0.25 mm. The material is an F4B board with a dielectric constant of 2.2. The second and third dielectric layers are also cubes with a side length of 16 mm and thicknesses h2 and h3 of 1.5 mm. The material is an F4B board with a dielectric constant of 2.2.

[0045] In this embodiment, the top polarization conversion layer can be obtained by etching copper foil. The first metal patch P1 and the second metal patch P2 are both "C" shaped with a bottom edge length l5 of 6.8 mm and a thickness g of 0.4 mm.

[0046] In this embodiment, the third metal patch P3 is square with a side length l4 of 5.6 mm, and the fourth metal patch P4 is a square ring with an outer side length l3 of 7 mm and a ring width g1 of 0.4 mm. The fifth, sixth, seventh, and eighth metal patches P5, P6, P7, and P8 are all rectangular patches with a length l2 of 5.9 mm and a width g2 of 0.3 mm. The ninth, tenth, eleventh, and twelfth metal patches P9, P10, P11, and P12 are arrow-shaped metal pieces with an arm length l1 of 3.3 mm and an arm width of 0.4 mm. The resistance values ​​of the first resistor R1, second resistor R2, third resistor R3, and fourth resistor R4 are all 200 ohms.

[0047] In this embodiment, the thirteenth metal patch P13 is square with a side length a1 of 4mm, and the fourteenth metal patch P14 is a square ring with an inner side length a2 of 6.5mm and an outer side length p of 7mm. The first PIN diode D1, the second PIN diode D2, the third PIN diode D3, and the fourth PIN diode D4 are all SMP1320.

[0048] In this embodiment, the metal microstrip line S can be obtained by etching copper foil, and has a length of 16 mm and a width of 0.2 mm; the metallized via h can be obtained by drilling holes in the second dielectric layer, and then electroplating the holes in a copper sulfate solution to coat the hole walls with copper, and the hole radius is 0.2 mm.

[0049] In this embodiment, the distance h11 between the first dielectric layer T1 and the second dielectric layer T2 is 6 mm, and the distance h33 between the second dielectric layer T2 and the third dielectric layer T3 is 8 mm. A bias voltage provided by a voltage control module is applied to the metal microstrip line S and the fourteenth metal patch P14.

[0050] Example 3

[0051] This embodiment describes the application process of the multifunctional active absorber with high-frequency reflective polarization conversion described in Embodiment 2.

[0052] The two operating states of the high-frequency band multifunctional active absorber with reflective polarization conversion can be obtained by setting the following voltage values ​​respectively:

[0053] (1) When the voltage applied to the metal microstrip line S is 0 volts and the voltage applied to the fourteenth metal patch P14 is greater than 0 volts, the first PIN diode D1, the second PIN diode D2, the third PIN diode D3, and the fourth PIN diode D4 are all in the off state. The high-frequency band has a multifunctional active absorber with reflection polarization conversion to realize the absorption-transmission-polarization conversion function.

[0054] (2) When the voltage applied to the metal microstrip line S is 5 volts and the voltage applied to the fourteenth metal patch P14 is greater than 0 volts, the first PIN diode D1, the second PIN diode D2, the third PIN diode D3 and the fourth PIN diode D4 are all in the conducting state, and the high-frequency band has a multifunctional active absorber with reflection polarization conversion to realize the absorption-reflection-polarization conversion function.

[0055] The reflection coefficient curves under two working conditions were obtained through simulation using HFSS software, and referenced... Figure 6 , Figure 6 Simulation results of the reflection coefficients of the multifunctional active absorber with reflective polarization conversion of this invention are presented for two operating states when the switching states of the first, second, third, and fourth PIN diodes change. Among them:

[0056] Figure 6 (a) The reflection coefficient and transmission coefficient of the TE / TM polarized incident wave when all four PIN diodes of the present invention are turned on;

[0057] Figure 6 (b) represents the reflection and transmission coefficients of the TE / TM polarized incident wave when all four PIN diodes of the present invention are disconnected.

[0058] The following is a detailed analysis of the two operating states of the multifunctional active absorbing device with reflection polarization conversion in the high-frequency band of this embodiment:

[0059] (1) When all four PIN diodes are disconnected, the multifunctional active absorber with reflective polarization conversion in the high-frequency band can realize the absorption-transmission-polarization conversion function in the range of 3.56-13.03GHz respectively;

[0060] (2) When all four PIN diodes are turned on, the multifunctional active absorber with reflection polarization conversion in the high-frequency band can realize the absorption-reflection-polarization conversion function in the range of 3.63-12.12GHz.

[0061] Simulation results show that by controlling the on / off state of the PIN diode, two independent and switchable combined states can be achieved on a single structure, namely absorption-transmission-polarization conversion and absorption-reflection-polarization conversion. This demonstrates that the present invention has the characteristics of multifunctionality and dual polarization.

[0062] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A multifunctional active absorber with high-frequency reflective polarization conversion, characterized in that, It includes several active absorber units arranged in a periodic manner; The active absorber unit includes a top polarization converter, a loss layer, a switching layer and a bias circuit layer, which are distributed from top to bottom. The top-level polarization converter includes a first metal patch (P1) and a second metal patch (P2) arranged symmetrically. The loss layer includes a third metal patch (P3), a fourth metal patch (P4), a first arrow-shaped metal patch, a second arrow-shaped metal patch, a third arrow-shaped metal patch, and a fourth arrow-shaped metal patch; the fourth metal patch (P4) is distributed outside the third metal patch (P3), and the tail ends of the four sets of arrow-shaped metal patches are respectively connected to the four sides of the fourth metal patch (P4); a first resistor (R1), a second resistor (R2), a third resistor (R3), and a fourth resistor (R4) are respectively connected to the four sets of arrow-shaped metal patches; The switching layer includes a thirteenth metal patch (P13) and a fourteenth metal patch (P14), with the fourteenth metal patch (P14) distributed outside the thirteenth metal patch (P13); a first PIN diode (D1), a second PIN diode (D2), a third PIN diode (D3), and a fourth PIN diode (D4) are connected between the thirteenth metal patch (P13) and the fourteenth metal patch (P14); The first PIN diode (D1) and the first resistor (R1) are connected in parallel between the first metal patch (P1) and the second metal patch (P2). The second PIN diode (D2) and the second resistor (R2) are connected in parallel between the second metal patch (P2) and the third metal patch (P3). The third PIN diode (D3) and the third resistor (R3) are connected in parallel between the third metal patch (P3) and the fourth metal patch (P4). The fourth PIN diode (D4) and the fourth resistor (R4) are connected in parallel between the fourth metal patch (P4) and the first metal patch (P1). The fourteenth metal patch (P14) and the bias circuit layer provide bias voltage for the PIN diodes, control the on / off state of the four sets of PIN diodes, and realize the absorption-transmission-polarization conversion function or the absorption-reflection-polarization conversion function.

2. The multifunctional active absorber with high-frequency reflective polarization conversion according to claim 1, characterized in that, The top-level polarization converter also includes a first dielectric substrate (T1), and the first metal patch (P1) and the second metal patch (P2) are disposed on the first dielectric substrate (T1); The loss layer further includes a second dielectric substrate (T2), and the third metal patch (P3), the fourth metal patch (P4), the first arrow-shaped metal patch, the second arrow-shaped metal patch, the third arrow-shaped metal patch and the fourth arrow-shaped metal patch are disposed on the second dielectric substrate (T2).

3. The multifunctional active absorber with high-frequency reflective polarization conversion according to claim 2, characterized in that, The first metal patch (P1) and the second metal patch (P2) are double "C" shaped metal patches, symmetrically distributed; the first metal patch (P1) and the second metal patch (P2) are located at the center of the first dielectric substrate (T1), and the axis of symmetry of the first metal patch (P1) and the second metal patch (P2) coincides with the diagonal of the first dielectric substrate (T1).

4. The multifunctional active absorber with high-frequency reflective polarization conversion according to claim 2, characterized in that, The third metal patch (P3) has a square structure and is located at the center of the loss layer. The fourth metal patch (P4) has a square ring structure and is located outside the third metal patch (P3). The center point of the fourth metal patch (P4) coincides with the center point of the third metal patch (P3). The first arrow-shaped metal patch includes a fifth metal patch (P5) and a ninth metal patch (P9), the second arrow-shaped metal patch includes a sixth metal patch (P6) and a tenth metal patch (P10), the third arrow-shaped metal patch includes a seventh metal patch (P7) and an eleventh metal patch (P11), and the fourth arrow-shaped metal patch includes an eighth metal patch (P8) and a twelfth metal patch (P12). The fifth metal patch (P5), sixth metal patch (P6), seventh metal patch (P7), and eighth metal patch (P8) are all rectangular metal strips, with one end connected to the center point of each of the four sides of the fourth metal patch (P4); the ninth metal patch (P9), tenth metal patch (P10), eleventh metal patch (P11), and twelfth metal patch (P12) are all equilateral "L"-shaped metal strips, respectively disposed at the other end of the fifth metal patch (P5), sixth metal patch (P6), seventh metal patch (P7), and eighth metal patch (P8), forming an arrowhead structure; the first resistor (R1), second resistor (R2), third resistor (R3), and fourth resistor (R4) are respectively connected to the fifth metal patch (P5), sixth metal patch (P6), seventh metal patch (P7), and eighth metal patch (P8); The fifth metal patch (P5), the sixth metal patch (P6), the seventh metal patch (P7), and the eighth metal patch (P8) coincide with the diagonal of the second dielectric substrate (T2).

5. The multifunctional active absorber with high-frequency reflective polarization conversion according to claim 1, characterized in that, The thirteenth metal patch (P13) has a square structure and is located at the center of the switching layer. The fourteenth metal patch (P14) has a square ring structure and is located outside the thirteenth metal patch (P13). The center point of the fourteenth metal patch (P14) coincides with the center point of the thirteenth metal patch (P13).

6. The multifunctional active absorber with high-frequency reflective polarization conversion according to claim 1, characterized in that, The bias circuit layer includes a third dielectric layer (T3), metallized vias (h), and a metal microstrip line (S); The metal microstrip line (S) is disposed on the third dielectric layer (T3), and the metallized via (h) is disposed at the center of the third dielectric layer (T3).

7. The multifunctional active absorber with high-frequency reflective polarization conversion according to claim 6, characterized in that, The metal microstrip line (S) passes through the metallized via (h) and is electrically connected to the thirteenth metal patch (P13) through the metallized via (h), providing bias voltage for the first PIN diode (D1), the second PIN diode (D2), the third PIN diode (D3) and the fourth PIN diode (D4).

8. The multifunctional active absorber with high-frequency reflective polarization conversion according to claim 1, characterized in that, The switching layer achieves two independently switchable combinations of absorption-transmission-polarization conversion and absorption-reflection-polarization conversion by switching the first PIN diode (D1), the second PIN diode (D2), the third PIN diode (D3), and the fourth PIN diode (D4). Specifically: When the first PIN diode (D1), the second PIN diode (D2), the third PIN diode (D3), and the fourth PIN diode (D4) are all turned on, the multifunctional active absorber with reflective polarization conversion in the high-frequency band can realize the absorption-transmission-polarization conversion function in the low-frequency, mid-frequency, and high-frequency bands. When the first PIN diode (D1), the second PIN diode (D2), the third PIN diode (D3), and the fourth PIN diode (D4) are all disconnected, the multifunctional active absorber with high-frequency reflective polarization conversion can realize the absorption-reflection-polarization conversion function in the low-frequency, mid-frequency, and high-frequency bands.

9. The multifunctional active absorber with high-frequency reflective polarization conversion according to claim 1, characterized in that, The active absorber comprises M×N periodically arranged active absorber units, where M≥2 and N≥2.

Images