Switchable dual-passband frequency selection wave absorber unit and wave absorber

Abstract

The invention discloses a switchable dual-passband frequency selection wave absorber unit and a wave absorber, and belongs to the field of electromagnetic protection, the switchable dual-passband frequency selection wave absorber unit comprises a first metal patch layer, a first dielectric substrate, a second metal patch layer and a second dielectric substrate which are stacked in sequence; the first metal patch layer comprises four square ring parts and four connecting sections; the second metal patch layer comprises a central patch, a first ring piece and a second ring piece, the central patch is nested in the first ring piece, and the first ring piece is nested in the second ring piece; four first photodiodes are arranged between the central patch and the first ring piece, one end of each first photodiode is connected with the central patch, the other end of each first photodiode is connected with the first ring piece, four second photodiodes are arranged between the first ring piece and the second ring piece, one end of each second photodiode is connected with the first ring piece, and the other end of each second photodiode is connected with the second ring piece. Therefore, the applicable frequency range of the wave-absorbing body can be improved, and the communication frequency band of the radar with the wave-absorbing body can be increased.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic protection, and in particular relates to a switchable dual-passband frequency selective absorber unit and an absorber. Background Art

[0002] With the development of electromagnetic wave technology, the electromagnetic environment is becoming increasingly complex. In modern communications, how to effectively control or suppress the characteristic signals of the target, significantly reduce the radar cross section (RCS) of the antenna system, and achieve radar stealth has always been a difficult problem that needs to be solved urgently. At present, frequency selective absorbers are a common technology for achieving radar stealth. Frequency selective absorbers (FSR) are periodic structures that have the characteristics of transmitting in certain frequency bands and absorbing in other frequency bands. By absorbing and transmitting waves through frequency selective absorbers, it can ensure that the radar can communicate normally and achieve the stealth function of the radar.

[0003] The common frequency selective absorber currently includes a lossy layer, a lossless layer and a dielectric layer between the two. With this structure, the lossless layer can achieve the regulation and frequency selection characteristics of electromagnetic waves, and the lossy layer can achieve energy dissipation and absorption, so that the absorber can absorb waves within a specific frequency range and reflect or transmit within other frequency ranges. However, the applicable frequency range of the absorber with this structure is single, resulting in a limited communication band for radars with this absorber. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a switchable dual-passband frequency selective absorber unit and an absorber. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0005] In a first aspect, the present invention provides a switchable dual-passband frequency selective absorber unit, comprising a first metal patch layer, a first dielectric substrate, a second metal patch layer and a second dielectric substrate stacked in sequence;

[0006] The first metal patch layer includes four square ring parts and four connecting segments, each square ring part is an open ring structure, two adjacent square ring parts are connected by a connecting segment, and the four square ring parts and the four connecting segments together form a closed ring structure;

[0007] The second metal patch layer includes a central patch, a first ring piece and a second ring piece, the central patch is nested in the first ring piece, the first ring piece is nested in the second ring piece, there is a gap between the central patch and the first ring piece, and there is a gap between the first ring piece and the second ring piece;

[0008] Four first photodiodes are arranged between the central patch and the first ring piece, one end of the first photodiode is connected to the central patch, and the other end is connected to the first ring piece, and four second photodiodes are arranged between the first ring piece and the second ring piece, one end of the second photodiode is connected to the first ring piece, and the other end is connected to the second ring piece.

[0009] In one embodiment of the present invention, the central patch is a rectangular patch, the first ring piece and the second ring piece are both square ring structures, the axis of the first ring piece passes through the center of the central patch and the center of the second dielectric substrate at the same time, and the second ring piece and the first ring piece are coaxially arranged;

[0010] The four first photodiodes are respectively connected to the center positions of the four side edges of the central patch, and the four second photodiodes are respectively connected to the center positions of the four side edges of the first ring piece.

[0011] In one embodiment of the present invention, the four square ring portions have the same size, and the four square ring portions are centrally symmetrical with respect to the center of the first dielectric substrate;

[0012] Each square ring portion corresponds to a second photodiode.

[0013] In one embodiment of the present invention, a resistor is provided on each connecting segment.

[0014] In one embodiment of the present invention, the square ring portion includes a first rectangular side, two second rectangular sides and two third rectangular sides, the first rectangular side is arranged along the width direction of the first dielectric substrate, the first ends of the two second rectangular sides are respectively connected to the two ends of the first rectangular side, the second ends of the two second rectangular sides are respectively connected to the first ends of the two third rectangular sides, and there is a gap between the second ends of the two third rectangular sides and they are respectively connected to a connecting section.

[0015] In one embodiment of the present invention, the connecting section includes a first straight edge, a slanted edge, and a second straight edge that are sequentially connected, and the resistor is disposed on the slanted edge.

[0016] In one embodiment of the present invention, a plurality of T-shaped pieces are arranged in each square ring portion, each T-shaped piece comprises a transverse piece and a longitudinal piece, one end of the longitudinal piece is connected to the transverse piece, and the other end is connected to the square ring portion, and the transverse piece and the longitudinal piece are perpendicular to each other.

[0017] In one embodiment of the present invention, three T-shaped pieces are provided, namely, a first T-shaped piece, a second T-shaped piece and a third T-shaped piece, the first T-shaped piece is connected to the middle position of the first rectangular side, the second T-shaped piece and the third T-shaped piece have the same size, and the second T-shaped piece and the third T-shaped piece are connected to two third rectangular sides respectively;

[0018] The length of the cross piece of the first T-shaped piece is greater than the total length of the cross pieces of the second T-shaped piece and the third T-shaped piece, the spacing between the first end of the cross piece of the first T-shaped piece and the second rectangular side is equal to the spacing between the second rectangular sides of the second T-shaped piece, and the spacing between the second end of the cross piece of the first T-shaped piece and the second rectangular side is equal to the spacing between the second rectangular sides of the third T-shaped piece.

[0019] In one embodiment of the present invention, the materials of the first metal patch layer and the second metal patch layer both include: one of copper, aluminum, and gold;

[0020] The first dielectric substrate and the second dielectric substrate are both made of flexible flame-resistant materials.

[0021] In a second aspect, the present invention provides a switchable dual-passband frequency selective absorber, comprising a plurality of absorber units distributed in a matrix, wherein the absorber units are the switchable dual-passband frequency selective absorber units provided by the above-mentioned solution.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] In the above scheme of the present application, the switchable dual-passband frequency selective absorber unit includes a first metal patch layer, a first dielectric substrate, a second metal patch layer and a second dielectric substrate which are stacked in sequence; the first metal patch layer includes four square ring parts and four connecting segments, each square ring part is an open ring structure, two adjacent square ring parts are connected by a connecting segment, and the four square ring parts and the four connecting segments together form a closed loop structure; the second metal patch layer includes a central patch, a first ring piece and a second ring piece, the central patch is nested in the first ring piece, the first ring piece is nested in the second ring piece, there is a gap between the central patch and the first ring piece, and there is a gap between the first ring piece and the second ring piece; four first photodiodes are arranged between the central patch and the first ring piece, one end of the first photodiode is connected to the central patch, and the other end is connected to the first ring piece, four second photodiodes are arranged between the first ring piece and the second ring piece, one end of the second photodiode is connected to the first ring piece, and the other end is connected to the second ring piece. With this structure, the first metal layer can be used as a lossy layer to absorb external electromagnetic wave energy and achieve in-band transmission, and the second metal layer can be used as a lossless layer to achieve electromagnetic wave regulation and frequency selection, thereby achieving wave absorption and wave transmission, thereby ensuring that the radar can communicate normally and achieving the stealth function of the radar. In addition, the first metal patch layer and the second metal patch layer can form a resonant structure, using the resonance effect to reflect the transmitted electromagnetic waves to improve the wave absorbing effect of the absorber. At the same time, in the present application, by adjusting the conduction or cutoff of the first photodiode, the central patch and the first ring patch can be electrically connected or disconnected, thereby changing the equivalent impedance and resonance characteristics of the second metal patch layer, and then changing the transmission and reflection characteristics of the electromagnetic wave on the absorber; by adjusting the conduction or cutoff of the second photodiode, the first ring patch and the second ring patch can be electrically connected or disconnected, thereby changing the equivalent impedance and resonance characteristics of the second metal patch layer, and then changing the transmission and reflection characteristics of the electromagnetic wave on the absorber. Therefore, by adjusting the conduction or cutoff of the first photodiode and the second photodiode, the transmission characteristics and reflection characteristics of the two passbands can be switched, so that the absorber can absorb and transmit waves within the frequency range of the two passbands, thereby improving the applicable frequency range of the absorber, and then increasing the communication band of the radar with the absorber.

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of a switchable dual-passband frequency selective absorber unit provided by an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of the first metal patch layer in an embodiment of the present invention Figure 1 ;

[0027] Figure 3 Schematic diagram of the first metal patch layer in an embodiment of the present invention Figure 2 ;

[0028] Figure 4 is a schematic diagram of a second metal patch layer in an embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of a switchable dual-passband frequency selective absorber provided by an embodiment of the present invention;

[0030] Figure 6 is a schematic diagram of S parameters and absorptivity of the absorber unit in an embodiment of the present invention when both the first photodiode and the second photodiode are cut off in the TE polarization mode;

[0031] Figure 7 It is a schematic diagram of S parameters and absorptivity of an absorber unit provided by an embodiment of the present invention when the first photodiode is turned on and the second photodiode is turned off in a TE polarization mode;

[0032] Figure 8 It is a schematic diagram of S parameters and absorptivity of an absorber unit provided by an embodiment of the present invention when the first photodiode is turned off and the second photodiode is turned on in a TE polarization mode;

[0033] Fig. 9 It is a comparison diagram of S parameters of the absorber unit provided by an embodiment of the present invention in the TE polarization mode and the TM polarization mode in three modes of the photodiode;

[0034] Fig.10 It is a schematic diagram of S parameters and absorptivity at different angles when the first photodiode and the second photodiode are both cut off in the TE polarization mode of the absorber unit provided by an embodiment of the present invention;

[0035] Fig.11 It is a schematic diagram of S parameters and absorptivity at different angles when the first photodiode of the absorber unit provided by an embodiment of the present invention is turned on and the second photodiode is turned off in the TE polarization mode;

[0036] Fig.12 It is a schematic diagram of S parameters and absorptivity at different angles when the first photodiode of the absorber unit provided by an embodiment of the present invention is turned off and the second photodiode is turned on in the TE polarization mode.

[0037] Figure numerals: 1-first metal patch layer, 11-square ring portion, 111-first rectangular side, 112-second rectangular side, 113-third rectangular side, 12-connecting section, 121-first straight side, 122-hypotenuse, 123-second straight side, 13-T-shaped piece, 131-first T-shaped piece, 132-second T-shaped piece, 133-third T-shaped piece, 2-first dielectric substrate, 3-second metal patch layer, 31-center patch, 32-first ring piece, 33-second ring piece, 4-second dielectric substrate, 5-first photodiode, 6-second photodiode, 7-resistance. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0039] Embodiment 1:

[0040] See also Figure 1 , Figure 2 , Figure 3 and Figure 4 The embodiment of the present invention provides a switchable dual-passband frequency selective absorber unit, comprising a first metal patch layer 1, a first dielectric substrate 2, a second metal patch layer 3 and a second dielectric substrate 4 which are stacked in sequence; the first metal patch layer 1 comprises four square ring portions 11 and four connecting segments 12, each square ring portion 11 is an open ring structure, two adjacent square ring portions 11 are connected by a connecting segment 12, and the four square ring portions 11 and the four connecting segments 12 together form a closed loop structure; the second metal patch layer 3 comprises a central patch 31, a first ring piece 32 and a second ring piece 33, the central patch The patch 31 is nested in the first ring piece 32, the first ring piece 32 is nested in the second ring piece 33, there is a gap between the central patch 31 and the first ring piece 32, and there is a gap between the first ring piece 32 and the second ring piece 33; four first photodiodes 5 are arranged between the central patch 31 and the first ring piece 32, one end of the first photodiode 5 is connected to the central patch 31, and the other end is connected to the first ring piece 32, four second photodiodes 6 are arranged between the first ring piece 32 and the second ring piece 33, one end of the second photodiode 6 is connected to the first ring piece 32, and the other end is connected to the second ring piece 33.

[0041] In some embodiments of the present application, a frequency selective absorber (Frequency Selective Surface, FSS) is a structure that can selectively absorb or reflect electromagnetic waves of a specific frequency.

[0042] In some embodiments of the present application, a photodiode is an optoelectronic semiconductor device that converts an optical signal into an electrical signal.

[0043] In some embodiments of the present application, when the first photodiode 5 is turned on, the central patch 31 and the first ring piece 32 are electrically connected, and when the first photodiode 5 is turned off, the central patch 31 and the first ring piece 32 are disconnected.

[0044] In some embodiments of the present application, when the second photodiode 6 is turned on, the first ring piece 32 and the second ring piece 33 are electrically connected, and when the second photodiode 6 is turned off, the first ring piece 32 and the second ring piece 33 are disconnected.

[0045] In some embodiments of the present application, when the second metal patch layer 3 is composed of the central patch 31, the first ring patch 32 and the second ring patch 33, the second metal patch layer 3 can realize a dual-passband frequency selective surface, which has the advantages of simple structure and convenient adjustment of the resonance points of the two passbands so as to align with the passband resonance point of the lossless layer. The in-band transmission and out-of-band reflection are enhanced through the resonance effect, further enhancing the wave absorption effect.

[0046] In some embodiments of the present application, by adjusting the conduction and cutoff of the first photodiode 5 and the second photodiode 6, the surface current of the metal structure under the incidence of electromagnetic waves can be changed, and the equivalent impedance of the second metal patch layer 3 can be adjusted, thereby achieving control over the two states of transmission and reflection.

[0047] In some embodiments of the present application, when the first photodiode 5 and the second photodiode 6 are both turned off, the absorber unit exhibits a transmission effect in the frequency ranges of 4.3 GHz-6.0 GHz and 9.8 GHz-12.1 GHz. When the first photodiode 5 is turned on and the second photodiode 6 is turned off, the absorber unit exhibits a transmission effect in the frequency range of 4.3 GHz-6.0 GHz and a reflection effect in the frequency range of 9.8 GHz-12.1 GHz. When the first photodiode 5 is turned off and the second photodiode 6 is turned on, the absorber unit exhibits a reflection effect in the frequency range of 4.3 GHz-6.0 GHz and a transmission effect in the frequency range of 9.8 GHz-12.1 GHz.

[0048] In the above scheme of the present application, the switchable dual-passband frequency selective absorber unit includes a first metal patch layer 1, a first dielectric substrate 2, a second metal patch layer 3 and a second dielectric substrate 4 which are stacked in sequence; the first metal patch layer 1 includes four square ring portions 11 and four connecting segments 12, each square ring portion 11 is an open ring structure, two adjacent square ring portions 11 are connected by a connecting segment 12, and the four square ring portions 11 and the four connecting segments 12 together form a closed loop structure; the second metal patch layer 3 includes a central patch 31, a first ring piece 32 and a second ring piece 33, the central patch 3 1 is nested in the first ring piece 32, the first ring piece 32 is nested in the second ring piece 33, there is a gap between the central patch 31 and the first ring piece 32, and there is a gap between the first ring piece 32 and the second ring piece 33; four first photodiodes 5 are arranged between the central patch 31 and the first ring piece 32, one end of the first photodiode 5 is connected to the central patch 31, and the other end is connected to the first ring piece 32, four second photodiodes 6 are arranged between the first ring piece 32 and the second ring piece 33, one end of the second photodiode 6 is connected to the first ring piece 32, and the other end is connected to the second ring piece 33. With this structure, the first metal layer can be used as a lossy layer to absorb external electromagnetic wave energy and realize in-band transmission, and the second metal layer can be used as a lossless layer to realize electromagnetic wave regulation and frequency selection, so as to realize wave absorption and wave transmission, thereby ensuring that the radar can communicate normally and realizing the stealth function of the radar. In addition, the first metal patch layer 1 and the second metal patch layer 3 can form a resonant structure, and the resonance effect is used to reflect the transmitted electromagnetic waves to improve the absorbing effect of the absorber. At the same time, in the present application, by adjusting the conduction or cutoff of the first photodiode 5, the central patch 31 and the first ring patch 32 can be electrically connected or disconnected, thereby changing the equivalent impedance and resonance characteristics of the second metal patch layer 3, and then changing the transmission and reflection characteristics of the electromagnetic wave on the absorber; by adjusting the conduction or cutoff of the second photodiode 6, the first ring patch 32 and the second ring patch 33 can be electrically connected or disconnected, thereby changing the equivalent impedance and resonance characteristics of the second metal patch layer 3, and then changing the transmission and reflection characteristics of the electromagnetic wave on the absorber. Therefore, by adjusting the conduction or cutoff of the first photodiode 5 and the second photodiode 6, the transmission characteristics and reflection characteristics of the two passbands can be switched, so that the absorber can absorb and transmit waves within the frequency range of the two passbands, thereby improving the applicable frequency range of the absorber, and then increasing the communication band of the radar with the absorber.

[0049] It can be understood that the present application can realize the switching of the absorber unit between the transmission mode and the reflection mode by adjusting the first photodiode 5 and the second photodiode 6 to be turned on or off. The principle mainly depends on the regulation of the surface current of the second metal patch layer 3 by the first photodiode 5 and the second photodiode 6. When the frequency selective surface presents the transmission effect and the reflection effect, the distribution of the surface current is different. When the first photodiode 5 or the second photodiode 6 is turned off, the metal on both sides of the first photodiode 5 or the second photodiode 6 is not connected, and the surface current cannot pass. When the first photodiode 5 or the second photodiode 6 is turned on, the metal on both sides of the first photodiode 5 or the second photodiode 6 is equivalent to a piece of metal. At this time, the surface current will be redistributed, and the redistributed current will affect the performance of the frequency selective surface, thereby adjusting the equivalent impedance of the second metal patch layer 3, and then affecting the transmission and reflection characteristics of electromagnetic waves on the frequency selective surface.

[0050] In some embodiments of the present application, the above-mentioned absorber unit of the present application is compatible with various electromagnetic scenarios, has high stability, and can flexibly switch between transmission mode and reflection mode at frequencies of 4.3GHz-6.0GHz and 9.8GHz-12.1GHz to achieve dynamic regulation of electromagnetic waves. And the absorption effect at 2.7GHz-3.5GH and 6.7GHz-9.2GHz is more than 80%, achieving the effect of reducing the radar cross section (RCS).

[0051] In some embodiments of the present application, Figure 1 and Figure 4 As shown, the central patch 31 is a rectangular patch, the first ring piece 32 and the second ring piece 33 are both square ring structures, the axis of the first ring piece 32 passes through the center of the central patch 31 and the second dielectric substrate 4 at the same time, and the second ring piece 33 and the first ring piece 32 are coaxially arranged; the four first photodiodes 5 are respectively connected to the center positions of the four sides of the central patch 31, and the four second photodiodes 6 are respectively connected to the center positions of the four sides of the first ring piece 32. With this structure, by optimizing the shapes and positions of the central patch 31, the first ring piece 32 and the second ring piece 33, and by optimizing the connection positions of the four first photodiodes 5 and the four second photodiodes 6, the flow path of the current can be optimized, and the frequency selection performance of the second metal patch layer 3 is further optimized.

[0052] In some embodiments of the present application, Figure 4 As shown, the width W of the second ring 11 is 1 mm, and the outer length of the second ring body is L 11 15mm, inner length L 12 The width W of the first ring is 14 mm.12 is 3.2 mm, and the outer length L of the first ring body 13 11.4mm, inner length L 14 is 8.2 mm, and the side length L of the center patch 31 is 15 The distance between the first dielectric substrate 2 and the second dielectric substrate 4 is 9 mm. The side lengths of the first dielectric substrate 2 and the second dielectric substrate 4 are both 15 mm, and the thicknesses are both 0.5 mm.

[0053] In some embodiments of the present application, the four square ring portions 11 have the same size, and the four square ring portions 11 are centrally symmetrical relative to the center of the first dielectric substrate 2; each square ring portion 11 corresponds to a second photodiode 6. With this structure, when the four square ring portions 11 and the four connecting segments 12 together form a closed loop structure, multiple resonance points can be generated, thereby expanding the operating frequency range of the absorber unit, enhancing the resonance intensity of the electromagnetic wave, and improving the reflection or absorption efficiency of the electromagnetic wave of the target frequency. The four square ring portions 11 are centrally symmetrical relative to the center of the first dielectric substrate 2, and when each square ring portion 11 corresponds to a second photodiode 6, the first metal patch layer 1 has better angular stability and polarization stability, and optimizes the electromagnetic wave coupling effect of the absorber.

[0054] In some embodiments of the present application, the resonance point of the square ring structure may be around 4.4 GHz, achieving a transmission effect of the first passband.

[0055] In some embodiments of the present application, a resistor 7 is provided on each connecting section 12. With this structure, the resistor 7 provided on the connecting section 12 can introduce loss between the two square ring portions 11, thereby generating a damping effect on the resonance, further expanding the working bandwidth of the absorber, and the resistor 7 is loaded on the first metal patch layer 1 as a loss medium, which can convert the energy of the incident electromagnetic wave into heat energy dissipation, thereby improving the absorbing effect.

[0056] In some embodiments of the present application, the square ring portion 11 includes a first rectangular side 111, two second rectangular sides 112 and two third rectangular sides 113, the first rectangular side 111 is arranged along the width direction of the first dielectric substrate 2, the first ends of the two second rectangular sides 112 are respectively connected to the two ends of the first rectangular side 111, the second ends of the two second rectangular sides 112 are respectively connected to the first ends of the two third rectangular sides 113, there is a gap between the second ends of the two third rectangular sides 113 and they are respectively connected to a connecting section 12. With this structure, the structure of the square ring portion 11 is optimized, the first metal patch layer 1 is more convenient to process and shape, and the wave absorbing effect of the first metal patch layer 1 is improved.

[0057] In some embodiments of the present application, Figure 2 and Figure 3 As shown, the length L of the third rectangular side 113 is 4 is 2.0 mm, and the width W of the third rectangular side 113 is 4 The length L of the second rectangular side 112 is 0.3 mm. 5 is 3.0 mm, and the width W of the second rectangular side 112 is 5 The length L of the first rectangular side 111 is 0.3 mm. 6 is 5.2 mm, and the width W of the first rectangular side 111 is 6 It is 0.3mm.

[0058] In some embodiments of the present application, the connecting section 12 includes a first straight edge 121, a beveled edge 122, and a second straight edge 123 connected in sequence, and the resistor 7 is arranged on the beveled edge 122. With this structure, the structure of the connecting section 12 is optimized, making it more convenient to process and shape the first metal patch layer 1, and improving the wave absorbing effect of the first metal patch layer 1.

[0059] In some embodiments of the present application, Figure 2 and Figure 3 As shown, the length L of the first straight side 121 is 1 is 2.3 mm, and the width W of the first straight edge 121 is 1 The length L of the second straight edge 123 is 0.3 mm. 2 is 2.3 mm, and the width W of the second straight edge 123 is 2 The length L of the hypotenuse 122 is 0.3 mm. 3 is 1.4 mm, and the width W of the bevel 122 is 3 The thickness of the bevel 122 is 0.3 mm, and the inclination angle of the bevel 122 is 45°.

[0060] In some embodiments of the present application, a plurality of T-shaped pieces 13 are provided in each square ring portion 11, and each T-shaped piece 13 includes a transverse piece and a longitudinal piece, one end of the longitudinal piece is connected to the transverse piece, and the other end is connected to the square ring portion 11, and the transverse piece and the longitudinal piece are perpendicular to each other. With this structure, the T-shaped piece 13 can excite multiple resonant frequencies, so that the absorber can effectively absorb electromagnetic waves in multiple frequency bands, thereby improving the multi-band response capability. In addition, the T-shaped patches at different positions can enhance the overall performance of the absorber and improve the absorbing efficiency through electromagnetic coupling interaction. At the same time, by providing multiple T-shaped pieces 13, the equivalent capacitance and equivalent inductance of the structure can be changed, so that a resonance point near 9.2 GHz can be added, thereby achieving the transmission effect of the second passband.

[0061] In some embodiments of the present application, three T-shaped pieces 13 are provided, namely, a first T-shaped piece 131, a second T-shaped piece 132 and a third T-shaped piece 133. The first T-shaped piece 131 is connected to the middle position of the first rectangular side 111. The second T-shaped piece 132 and the third T-shaped piece 133 have the same size. The second T-shaped piece 132 and the third T-shaped piece 133 are respectively connected to the two third rectangular sides 113. The length of the cross piece of the first T-shaped piece 131 is greater than the total length of the cross piece of the second T-shaped piece 132 and the cross piece of the third T-shaped piece 133. The spacing between the first end of the cross piece of the first T-shaped piece 131 and the second rectangular side 112 is equal to the spacing between the second T-shaped piece 132 and the second rectangular side 112. The spacing between the second end of the cross piece of the first T-shaped piece 131 and the second rectangular side 112 is equal to the spacing between the second rectangular side 112 of the third T-shaped piece 133. With this structure, the arrangement positions and sizes of the three T-shaped pieces 13 are optimized, and the wave absorbing efficiency of the first metal patch layer 1 is further improved.

[0062] In some embodiments of the present application, Figure 2 and Figure 3 As shown, the length L of the transverse piece of the second T-shaped portion and the third T-shaped portion 7 1.4mm, width W 7 The length L of the longitudinal strips of the second T-shaped portion and the third T-shaped portion is 0.3 mm. 8 1.4mm, width W 8 The length L of the longitudinal piece of the first T-shaped portion is 0.4 mm. 9 0.5mm, width W 9 is 0.4 mm, and the length L of the horizontal piece of the first T-shaped portion is 10 3.4mm, width W 10 It is 0.3mm.

[0063] In some embodiments of the present application, the materials of the first metal patch layer 1 and the second metal patch layer 3 are both made of one of copper, aluminum, and gold; the materials of the first dielectric substrate 2 and the second dielectric substrate 4 are both made of flexible flame-resistant materials. With this structure, the wave absorbing and wave transmitting performance of the absorber can be further improved.

[0064] In some embodiments of the present application, the relative dielectric constant of the first dielectric substrate 2 is 2.65, the electric shear loss is 0.0001, the thickness of the first dielectric substrate 2 and the second dielectric substrate 4 is 0.5 mm, and the thickness of the first metal patch layer 1 and the second metal patch layer 3 is 0.017 mm to 0.035 mm. The side length of the first dielectric substrate 2 and the second dielectric substrate 4 is 15 mm. Exemplarily, the material of the first dielectric substrate 2 and the second dielectric substrate 4 is F4B plate.

[0065] In some embodiments of the present application, the surface size of the absorber unit is 15 mm*15 mm, which can meet the trend of miniaturized structure and the requirements of processing technology.

[0066] In some embodiments of the present application, in order to verify the performance of the frequency selective absorber with switchable transmission and reflection provided by the present embodiment, a number of performance simulation analyses were performed on the absorber unit using commercial simulation software.

[0067] See also Figures 6 to 9 , Figure 6 A schematic diagram showing the S parameters and the wave absorption rate of the absorber unit in the embodiment of the present invention when the first photodiode 5 and the second photodiode 6 are both cut off in the TE polarization mode; Figure 7 A schematic diagram showing S parameters and wave absorption rate of the absorber unit provided by an embodiment of the present invention when the first photodiode 5 is turned on and the second photodiode 6 is turned off in the TE polarization mode; Figure 8 A schematic diagram showing the S parameters and the wave absorption rate of the absorber unit provided by the embodiment of the present invention when the first photodiode 5 is turned off and the second photodiode 6 is turned on in the TE polarization mode; Fig. 9 A comparison diagram of S parameters of the TE polarization mode and the TM polarization mode of the absorber unit provided by the embodiment of the present invention in three modes of the photodiode is shown.

[0068] Depend on Figure 6 It can be seen from the return loss S11 and insertion loss S21 of (a) that when the first photodiode 5 and the second photodiode 6 are all cut off, the passband of the absorber unit of this embodiment is 4.3GHz-6.0GHz and 9.8GHz-12.1GHz, and the S11 curve is basically below -10dB, at this time the absorber unit is in ATAT state. Figure 6 (b) It can be seen that the wave absorption rate of the two absorption bands of the structure reaches more than 80%, and the wave transmittance of the passband reaches more than 90%.

[0069] Depend on Figure 7 It can be seen from the return loss S11 and insertion loss S21 of (a) that when the first photodiode 5 is turned on and the second photodiode 6 is turned off, the passband of the absorber unit of this embodiment is 4.3GHz-6.0GHz, and 9.8GHz-12.1GHz becomes a reflection state. Figure 7 (b) It can be seen that the absorption bands remain basically unchanged, the absorption rates of the two absorption bands reach more than 80%, the passband becomes only 4.3GHz-6.0GHz, and the transmittance reaches more than 90%.

[0070] Depend on Figure 8It can be seen from the return loss S11 and insertion loss S21 of (a) that when the first photodiode 5 is turned off and the second photodiode 6 is turned on, the passband of the absorber unit of this embodiment is 9.8 GHz-12.1 GHz, and 4.3 GHz-6.0 GHz becomes a reflection state. Figure 8 (b) It can be seen that the absorption rate of the first absorption band is over 80%, and the absorption rate of the second absorption band is reduced, but still over 70%. The passband becomes only 9.8GHz-12.1GHz, and the transmittance is over 90%.

[0071] Depend on Fig. 9 It can be seen that when the first photodiode 5 and the second photodiode 6 are both cut off, the first photodiode 5 is turned on, the second photodiode 6 is cut off, and the first photodiode 5 is cut off and the second photodiode 6 is turned on, the S parameter performance in the TE polarization mode and the TM polarization mode hardly changes, and the structure has excellent polarization stability.

[0072] In addition, in order to study the angular stability of the absorber unit of this embodiment, the frequency characteristics of the structure can be obtained by irradiating with incident waves at incident angles of 0°, 10°, 20° and 30° in the TE polarization mode. Figures 10 to 12 , Fig.10 A schematic diagram showing S parameters and wave absorption rates of the absorber unit provided by an embodiment of the present invention at different angles when the first photodiode 5 and the second photodiode 6 are both cut off in the TE polarization mode; Fig.11 A schematic diagram showing S parameters and wave absorption rates of the absorber unit provided by an embodiment of the present invention at different angles when the first photodiode 5 is turned on and the second photodiode 6 is turned off in the TE polarization mode; Fig.12 The schematic diagram shows the S parameters and wave absorption rate of the absorber unit provided by the embodiment of the present invention at different angles when the first photodiode 5 is turned off and the second photodiode 6 is turned on in the TE polarization mode. The absorber unit has good angle stability and excellent switching characteristics at 4.3GHz-6.0GHz and 9.8GHz-12.1GHz, and the influence of the absorption rate and the wave transmittance on the angle change is also small. Under the irradiation of electromagnetic incident waves at different angles, the frequency deviation is within an acceptable range, and it has excellent signal transmission capability and anti-interference capability. And by Fig.11 and Fig.12 It can be seen that the performance difference of the photodiode at different angles after switching is also within an acceptable range. Therefore, it can be concluded that the structure has excellent angular stability.

[0073] The present embodiment has a frequency selective absorber unit that can switch between transmission and reflection independently regulated for two passbands, and can flexibly switch between transmission mode and reflection mode near 4.3GHz-6.0GHz and 9.8GHz-12.1GHz, and has wave absorption capability at 2.7GHz-3.5GH and 6.7GHz-9.2GHz, and can take into account both signal transmission capability and RCS reduction capability in a variety of electromagnetic scenarios, and can switch between transmission and reflection of the passband as required. The surface structure provided in the present embodiment has good angular stability and polarization stability, and the resonant frequency and bandwidth change little when incident waves are irradiated at different angles, and the resonant frequency has no deviation when the incident wave is vertically irradiated (the incident angle is 0°) in TE and TM polarization modes, and has no effect on the structural performance.

[0074] Embodiment 2:

[0075] See also Figure 5 The present invention also provides a switchable dual-passband frequency selective absorber, comprising a plurality of absorber units distributed in a matrix, wherein the absorber units are the switchable dual-passband frequency selective absorber units provided in the above-mentioned embodiment 1.

[0076] The beneficial effects of the second embodiment of the present invention and its various implementations can be analyzed by referring to the beneficial effects of the first embodiment and its various implementations, which will not be described in detail here.

[0077] In some embodiments of the present application, the absorber units are arranged in a 5*5 matrix, or in a 10*10 matrix, or in a 20*20 matrix, or in a 40*40 matrix.

[0078] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0079] In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0080] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0081] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A switchable dual-passband frequency selective absorber unit, characterized in that: It includes a first metal patch layer, a first dielectric substrate, a second metal patch layer and a second dielectric substrate which are stacked in sequence; The first metal patch layer includes four square ring parts and four connecting segments, each of the square ring parts is an open ring structure, two adjacent square ring parts are connected by one connecting segment, and the four square ring parts and the four connecting segments together form a closed ring structure; The second metal patch layer includes a central patch, a first ring piece and a second ring piece, wherein the central patch is nested in the first ring piece, the first ring piece is nested in the second ring piece, there is a gap between the central patch and the first ring piece, and there is a gap between the first ring piece and the second ring piece; Four first photodiodes are arranged between the central patch and the first ring piece, one end of the first photodiode is connected to the central patch, and the other end is connected to the first ring piece, and four second photodiodes are arranged between the first ring piece and the second ring piece, one end of the second photodiode is connected to the first ring piece, and the other end is connected to the second ring piece.

2. The switchable dual-passband frequency selective absorber unit according to claim 1, characterized in that: The central patch is a rectangular patch, the first ring piece and the second ring piece are both square ring structures, the axis of the first ring piece passes through the center of the central patch and the center of the second dielectric substrate at the same time, and the second ring piece and the first ring piece are coaxially arranged; The four first photodiodes are respectively connected to the center positions of the four side edges of the central patch, and the four second photodiodes are respectively connected to the center positions of the four side edges of the first ring piece.

3. The switchable dual-passband frequency selective absorber unit according to claim 2, characterized in that: The four square ring portions have the same size, and are centrally symmetrical relative to the center of the first dielectric substrate. Each of the square ring parts corresponds to one of the second photodiodes.

4. The switchable dual-passband frequency selective absorber unit according to claim 1, characterized in that: A resistor is arranged on each of the connecting sections.

5. The switchable dual-passband frequency selective absorber unit according to claim 4, characterized in that: The square ring portion includes a first rectangular side, two second rectangular sides and two third rectangular sides, the first rectangular side is arranged along the width direction of the first dielectric substrate, the first ends of the two second rectangular sides are respectively connected to the two ends of the first rectangular side, the second ends of the two second rectangular sides are respectively connected to the first ends of the two third rectangular sides, and there is a gap between the second ends of the two third rectangular sides and they are respectively connected to one of the connecting sections.

6. The switchable dual-passband frequency selective absorber unit according to claim 5, characterized in that: The connecting section includes a first straight edge, a slanted edge, and a second straight edge which are connected in sequence, and the resistor is arranged on the slanted edge.

7. The switchable dual-passband frequency selective absorber unit according to claim 6, characterized in that: A plurality of T-shaped pieces are arranged in each of the square ring parts, and each of the T-shaped pieces comprises a transverse piece and a longitudinal piece, one end of the longitudinal piece is connected to the transverse piece, and the other end is connected to the square ring part, and the transverse piece and the longitudinal piece are perpendicular to each other.

8. The switchable dual-passband frequency selective absorber unit according to claim 7, characterized in that: The T-shaped pieces are provided with three pieces, namely a first T-shaped piece, a second T-shaped piece and a third T-shaped piece, the first T-shaped piece is connected to the middle position of the first rectangular side, the second T-shaped piece and the third T-shaped piece have the same size, and the second T-shaped piece and the third T-shaped piece are connected to two third rectangular sides respectively; The length of the cross piece of the first T-shaped piece is greater than the total length of the cross pieces of the second T-shaped piece and the third T-shaped piece, the spacing between the first end of the cross piece of the first T-shaped piece and the second rectangular side is equal to the spacing between the second rectangular sides of the second T-shaped piece, and the spacing between the second end of the cross piece of the first T-shaped piece and the second rectangular side is equal to the spacing between the second rectangular sides of the third T-shaped piece.

9. The switchable dual-passband frequency selective absorber unit according to claim 1, characterized in that: The materials of the first metal patch layer and the second metal patch layer both include: one of copper, aluminum, and gold; The first dielectric substrate and the second dielectric substrate are both made of flexible flame-resistant materials.

10. A switchable dual-passband frequency selective absorber, characterized in that: The invention comprises a plurality of absorber units distributed in a matrix, wherein the absorber units are switchable dual-passband frequency selective absorber units as claimed in any one of claims 1 to 9.

Images