A cross-band electromagnetic protection energy selective surface with extremely wide bandwidth

Abstract

The present invention discloses a cross-band electromagnetic protection energy selective surface with extremely wide bandwidth, which includes a multi-layer structure band-pass frequency selective surface and a control element. The control element is loaded on the top of the multi-layer structure band-pass frequency selective surface; the multi-layer structure band-pass frequency selective surface has out-of-band suppression performance, and the control element has energy self-adaptive conduction performance. In the case of low-power microwave incidence, the control element remains in the cut-off state, so that the energy selective surface remains as a band-pass frequency selective surface structure with wide-band out-of-band suppression characteristics; in the case of high-power microwave signal incidence, the control element conducts, thereby changing the response characteristics of the original frequency selective surface and achieving effective shielding of extremely wide-band electromagnetic signals. The present invention combines a band-pass frequency selective surface with a PIN diode to enable it to have cross-band electromagnetic protection ability with extremely wide bandwidth.

Description

Technical Field

[0001] The present invention relates to an energy selective surface in the field of electromagnetic protection, and particularly to a cross-band electromagnetic protection energy selective surface with extremely wide bandwidth. Background Art

[0002] With the continuous development of high-power microwave weapon technology, higher challenges are posed to the front-door coupling protection of electronic devices and communication systems. As a spatial filter, the frequency selective surface has good frequency selective characteristics. Through the coupling effect between units, it can realize the band-pass characteristic while suppressing the electromagnetic waves outside the ultra-wideband band. The energy selective surface is based on the frequency selective surface and further realizes the energy selective characteristic of spatial electromagnetic waves by loading control elements with switching characteristics such as electrically controlled PIN diodes. When the energy of the spatial electromagnetic wave is small, the PIN diode in the energy selective surface is in the cut-off state, and the spatial electromagnetic wave can be transmitted through the passband of the frequency selective surface. When the energy of the spatial electromagnetic wave exceeds the conduction threshold of the PIN diode, the PIN diode is in the conduction state, realizing the cross-band reflection of the spatial electromagnetic wave, so as to achieve the ultra-wideband electromagnetic protection effect. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to provide a cross-band electromagnetic protection energy selective surface with extremely wide bandwidth. By using the interlayer coupling and miniaturization technology, a band-pass type frequency selective surface with excellent out-of-band suppression is designed and combined with a PIN diode to endow it with electromagnetic protection ability with extremely wide bandwidth.

[0004] Technical Solution: The present invention discloses a cross-band electromagnetic protection energy selective surface with extremely wide bandwidth, which includes a multi-layer structure band-pass type frequency selective surface and a control element. The control element is loaded on the top of the multi-layer structure band-pass type frequency selective surface; the multi-layer structure band-pass type frequency selective surface has out-of-band suppression performance, and the control element has energy self-adaptive conduction performance. In the case of low-power microwave incidence, the control element remains in the cut-off state, so that the energy selective surface remains as a band-pass type frequency selective surface structure with wideband out-of-band suppression characteristics; in the case of high-power microwave signal incidence, the control element conducts, thereby changing the response characteristics of the original frequency selective surface and realizing the effective shielding of extremely wideband electromagnetic signals.

[0005] Preferably, the control element is a PIN diode.

[0006] Preferably, the multi-layered structure band-pass frequency selective surface is composed of an array arrangement of N×N periodic units, where N is a natural number greater than or equal to 1. The periodic unit includes, from top to bottom in sequence: a first metal layer, a first dielectric layer, a second metal layer, a first foam layer, a third metal layer, a second dielectric layer, a second foam layer, a fourth metal layer, a third dielectric layer, and a fifth metal layer. The control element is disposed on the upper surface of the first metal layer.

[0007] Preferably, the first metal layer and the fifth metal layer are cross-slot folded layers with the same structure. From the center point of a complete rectangular metal patch, bending slots are respectively opened in the directions perpendicular to the four rectangular sides, forming a cross-slot structure with 90° rotational symmetry. Four control elements are disposed at the second turning corners of two adjacent slots of the first metal layer.

[0008] Preferably, the four control elements are bonded to the slots opened between adjacent metal rectangular patches through conductive adhesive.

[0009] Preferably, the second metal layer is a square metal patch with interdigital bends, including four mutually independent metal patches. Each metal patch includes two mutually independent bent metal patches. The four mutually independent metal patches form a 90° rotational symmetry structure, and the bending shape is square or triangular.

[0010] Preferably, the third metal layer is a cross-slot grid layer, including an outer square ring metal patch and an inner bent cross-shaped metal patch. Starting from the center of the outer square ring metal patch, four bent metal patches are respectively extended in the directions perpendicular to the four sides of the square ring, forming a bent cross-shaped metal patch with 90° rotational symmetry; the size of the outer square ring metal patch is the same as that of the dielectric substrate, and the bending shape of the inner bent cross-shaped metal patch is square or triangular.

[0011] Preferably, the fourth metal layer is a fractal metal patch layer, whose size is smaller than that of the dielectric layer, and the bending shape is square or triangular.

[0012] Preferably, the first dielectric layer, the second dielectric layer, and the third dielectric layer are dielectric substrates. The dielectric constant of the dielectric substrate satisfies: 2.2 ≤ ε ≤ 20, and its thickness satisfies: 0.01 mm ≤ h ≤ 10 mm.

[0013] Preferably, the thicknesses of the first foam layer and the second foam layer respectively satisfy: 0.01 mm ≤ h ≤ 10 mm.

[0014] Beneficial effects: Compared with the prior art, the advantages of the present invention are as follows: The band-pass frequency selective surface is combined with PIN diodes. The five-layer metal patch and the three-layer dielectric substrate constitute the frequency selection structure of the energy selection surface, and the PIN diodes realize the adaptive state conversion function of the ESS; the PIN diodes are in the cut-off state when low-power microwaves are incident, and the energy selection surface structure remains as a band-pass with an excellent out-of-band rejection frequency selective surface structure. When high-power microwaves are incident, they conduct, changing the original response characteristics of the frequency selective surface so that it can effectively shield electromagnetic signals; the energy selection surface has extremely strong adaptive protection capabilities, a wide operating frequency band, and an ultra-wide protection frequency band; in addition, two layers of foam layers are used instead of the traditional air layer, making the energy selection surface have a better support effect. Description of the Drawings

[0015] Figure 1 is a three-dimensional structure schematic diagram of an energy selection surface for cross-band electromagnetic protection with extremely large bandwidth in a specific embodiment of the present invention;

[0016] Figure 2 is a layered structure schematic diagram of an energy selection surface for cross-band electromagnetic protection with extremely large bandwidth in a specific embodiment of the present invention;

[0017] Figure 3 is a top view of the first metal layer in a specific embodiment of the present invention;

[0018] Figure 4 is a top view of the second metal layer in a specific embodiment of the present invention;

[0019] Figure 5 is a top view of the third metal layer in a specific embodiment of the present invention;

[0020] Figure 6 is a top view of the fourth metal layer in a specific embodiment of the present invention;

[0021] Figure 7 and Figure 8 is a schematic diagram of the simulation results of an energy selection surface for cross-band electromagnetic protection with extremely large bandwidth in a specific embodiment of the present invention;

[0022] In the figure: the first metal layer 101, the first dielectric layer 102, the second metal layer 103, the first foam layer 104, the third metal layer 105, the second dielectric layer 106, the second foam layer 107, the fourth metal layer 108, the third dielectric layer 109, the fifth metal layer 110, the first PIN diode 201, the second PIN diode 202, the third PIN diode 203, the fourth PIN diode 204. Specific Embodiments

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" is based on the orientation or positional relationship shown in the relevant drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention.

[0025] A band-pass type energy selection surface with extremely high electromagnetic protection bandwidth in this embodiment includes a multi-layer structure band-pass type frequency selection surface and a control element PIN diode. The control element PIN diode is loaded on the top of the multi-layer structure band-pass type frequency selection surface. The frequency selection surface is composed of an array arrangement of N×N periodic unit arrays, where N is a natural number greater than or equal to 1. The periodic unit structure is composed of five metal layers, two foam layers and three dielectric layers. Based on the frequency selection surface unit and four PIN diodes, a corresponding energy selection surface periodic unit structure is constructed. The PIN diodes are loaded on the top of the frequency selection surface unit. The frequency selection surface has good out-of-band rejection performance, while the PIN diodes have energy self-adaptive conduction performance, enabling the energy selection surface to have a wide operating frequency band, an ultra-wide protection frequency band and self-adaptive protection ability, that is, the energy selection surface has a band-pass characteristic of broadband out-of-band rejection at low energy and an ultra-wideband electromagnetic protection ability at high energy.

[0026] Such as Figure 1 and Figure 2As shown, the periodic unit structure of the energy selection surface includes a frequency selection surface unit and four PIN diodes. The frequency selection surface unit includes, from top to bottom in sequence: a first metal layer 101, a first dielectric layer 102, a second metal layer 103, a first foam layer 104, a third metal layer 105, a second dielectric layer 106, a second foam layer 107, a fourth metal layer 108, a third dielectric layer 109, and a fifth metal layer 110. That is, the first metal layer 101 and the second metal layer 103 are respectively attached to the upper and lower surfaces of the first dielectric layer 102, the third metal layer 105 is attached to the upper layer of the second dielectric layer 106, the first foam layer 104 is between the second metal layer 103 and the third metal layer 105, the fifth metal layer 110 and the fourth metal patch 108 are respectively attached to the bottom and top surfaces of the third dielectric layer (109), and the second foam layer 107 is between the second dielectric layer 106 and the fourth metal layer 108. Four PIN diodes are provided on the first metal layer 101.

[0027] As Figure 2 As shown, according to an embodiment of the present invention, the first dielectric layer 102, the second dielectric layer 106, and the third dielectric layer 109 are the main supporting materials of the entire energy selection surface, mainly playing a supporting role in mechanical properties. Furthermore, the dielectric substrates of the three dielectric layers are realized by using high-frequency circuit boards, such as Rogers 5880, Taixing Microwave F4B, Arlon, Taconic, etc. In this embodiment, the dielectric constant of the sandwich dielectric substrate satisfies: 2.2 ≤ ε ≤ 20, and its thickness satisfies: 0.01 mm ≤ h ≤ 10 mm.

[0028] As Figure 2 As shown, according to an embodiment of the present invention, the first foam layer 104 and the second foam layer 107 are also the main supporting materials of the entire energy selection surface, mainly playing a supporting role in mechanical properties. Its thickness satisfies: 0.01 mm ≤ h ≤ 10 mm.

[0029] As Figure 3As shown, in the specific embodiment of the present invention, the first metal layer 101 is a cross-slot folding layer, which is formed by a complete rectangular metal patch. Starting from the center point of the metal patch, bending slots are respectively opened in the directions perpendicular to the four rectangular sides to form a cross-slot structure with 90° rotational symmetry. The fifth metal layer 110 is the same cross-slot folding layer as the first metal layer 101. Among them, four PIN diodes are added at the second turning corners of adjacent two slots in the first metal layer 101, namely the first PIN diode 201, the second PIN diode 202, the third PIN diode 203 and the fourth PIN diode 204. The first metal layer 101 realizes the adaptive state conversion function of the ESS by loading four PIN diodes at the gap, achieving the effects of low insertion loss and high protection efficiency. The first PIN diode 201, the second PIN diode 202, the third PIN diode 203 and the fourth PIN diode 204 are adhered to the gap between adjacent metal rectangular patches by conductive adhesive, and there is no specific requirement for the orientation of the positive pole of the PIN diode.

[0030] As Figure 4 shown, in the specific embodiment of the present invention, the second metal layer 103 is a square metal patch with interdigital bends, including four mutually independent metal patches, and each metal patch includes two mutually independent bent metal patches; the four mutually independent metal patches form a 90° rotational symmetry structure. The shape of the second metal layer 103 includes but is not limited to square, triangular, etc.

[0031] As Figure 5 shown, in the specific embodiment of the present invention, the third metal layer 105 is a cross-slot grid layer, including an outer square ring metal patch and an inner bent cross-shaped metal patch. Starting from the center of the outer square ring metal patch, four bent metal patches are respectively extended in the directions perpendicular to the four sides of the square ring to form a bent cross-shaped metal patch with 90° rotational symmetry. The size of the outer square ring metal patch is the same as that of the dielectric substrate, and the bent shape of the inner bent cross-shaped metal patch includes but is not limited to square, triangular, etc.

[0032] As Figure 6 shown, in the specific embodiment of the present invention, the fourth metal layer 108 is a fractal metal patch layer, which is also a 90° rotational symmetry structure. The size of the fourth metal layer 108 is slightly smaller than that of the dielectric substrate, and its bent shape includes but is not limited to square, triangular, etc. The centers of the first metal layer 101, the second metal layer 103, the third metal layer 105, the fourth metal layer 108 and the fifth metal layer 110 are on the same central axis, forming the central axis of the energy selection surface unit.

[0033] In the case of low-power microwave incidence, the PIN diode remains in the cut-off state, making the energy selection surface maintain a band-pass type frequency selection surface structure with excellent out-of-band rejection characteristics; while in the case of high-power microwave signal incidence, the PIN diode conducts, thereby changing the response characteristics of the original frequency selection surface and achieving effective shielding of extremely broadband electromagnetic signals. The present invention innovates on the basis of the traditional energy selection surface, combines the band-pass type frequency selection surface with the PIN diode, and endows it with electromagnetic protection capabilities across extremely broadband frequency bands.

[0034] As Figure 7 and Figure 8 shown, to further illustrate the technical effects of this solution, an embodiment with a 5-layer structure was selected. Based on the foregoing solution settings, simulation analysis was carried out on it to test the performance of the energy selection surface. Among them, the abscissa is frequency and the ordinate is insertion loss. It can be seen that in the range of 2.05 GHz - 2.55 GHz, the insertion loss of this solution is always less than 1 dB, maintaining a relative bandwidth of 22%, and having good out-of-band steep drop characteristics. It can be seen that the protection performance is always greater than 10 dB in the frequency band of 0 GHz - 18 GHz, meeting the electromagnetic protection requirements of ultra-wideband protection.

[0035] The above content is only an example of the specific solution of the present invention. For the equipment and structures not described in detail therein, it should be understood that the existing general equipment and general methods in the art are adopted for implementation.

[0036] The above description is only one solution of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A cross-band electromagnetic protection energy selective surface with extremely large bandwidth, characterized in that: It comprises a multi-layer structure bandpass type frequency selective surface and a control element, wherein the control element is loaded on the top of the multi-layer structure bandpass type frequency selective surface; the multi-layer structure bandpass type frequency selective surface has out-of-band suppression performance, and the control element has energy adaptive conduction performance. Under the condition of low-power microwave incidence, the control element maintains a cut-off state, so that the energy selective surface maintains a bandpass type frequency selective surface structure with wideband out-of-band suppression characteristics; under the condition of high-power microwave signal incidence, the control element is turned on, thereby changing the response characteristics of the original frequency selective surface, and realizing effective shielding of extremely large broadband electromagnetic signals; The control element is a PIN diode; The multi-layer structure bandpass frequency selective surface is composed of an N×N periodic unit array arrangement, N is a natural number greater than or equal to 1, and the periodic units include, from top to bottom: a first metal layer (101), a first dielectric layer (102), a second metal layer (103), a first foam layer (104), a third metal layer (105), a second dielectric layer (106), a second foam layer (107), a fourth metal layer (108), a third dielectric layer (109) and a fifth metal layer (110); the first metal layer (101) and the fifth metal layer (110) are cross-groove folding layers with the same structure, starting from the center point of the metal patch, bending grooves are respectively opened in directions perpendicular to the four rectangular sides to form a 90° rotationally symmetrical cross-groove structure, and the first metal layer (101) and the fifth metal layer (110) are respectively formed. Four control elements are arranged at the second corners of two adjacent grooves of a metal layer (101); the second metal layer (103) is a square metal patch with interdigitated bends, comprising four independent metal patches, each of which comprises two independent bent metal patches, and the four independent metal patches form a 90° rotationally symmetrical structure; the third metal layer (105) is a cross-groove grid layer, comprising an outer layer of square ring metal patches and an inner layer of bent cross-shaped metal patches connected thereto, and starting from the center of the outer layer of square ring metal patches, four bent metal patches are respectively extended in directions perpendicular to the four square ring edges to form a 90° rotationally symmetrical bent cross-shaped metal patch; the fourth metal layer (108) is a fractal metal patch layer.

2. The cross-band electromagnetic protection energy selective surface with extremely large bandwidth according to claim 1 is characterized in that: The first metal layer (101) and the fifth metal layer (110) are made of a complete rectangular metal patch.

3. The cross-band electromagnetic protection energy selective surface with extremely large bandwidth according to claim 1 is characterized in that: The four control elements are bonded to the slots between adjacent metal rectangular patches by conductive adhesive.

4. The cross-band electromagnetic protection energy selective surface with extremely large bandwidth according to claim 1 is characterized in that: The bending shape of the metal patch is square or triangle.

5. The cross-band electromagnetic protection energy selective surface with extremely large bandwidth according to claim 1, characterized in that: The square ring metal patch of the outer layer of the third metal layer (105) has the same size as the dielectric substrate, and the bent cross-shaped metal patch of the inner layer has a bent shape of a square or a triangle.

6. The cross-band electromagnetic protection energy selective surface with extremely large bandwidth according to claim 1, characterized in that: The fourth metal layer (108) is smaller than the dielectric layer, and its bending shape is a square or a triangle.

7. The cross-band electromagnetic protection energy selective surface with extremely large bandwidth according to claim 1, characterized in that: The first dielectric layer (102), the second dielectric layer (106) and the third dielectric layer (109) are dielectric substrates, the dielectric constant of the dielectric substrates satisfies: 2.2≤ε≤20, and the thickness thereof satisfies: 0.01mm≤h≤10mm.

8. The cross-band electromagnetic protection energy selective surface with extremely large bandwidth according to claim 1, characterized in that: The thicknesses of the first foam layer (104) and the second foam layer (107) respectively satisfy: 0.01 mm≤h≤10 mm.

Images