An ultra-wideband passive electromagnetic shielding surface based on Kramers-Kronig relationship

Abstract

The present invention relates to an ultra-wideband passive electromagnetic shielding surface based on the Kramers-Kronig relationship, comprising a plurality of ultra-wideband passive electromagnetic shielding units, which are arranged according to the incident angle of the radiated electromagnetic wave to form the ultra-wideband passive electromagnetic shielding surface. The ultra-wideband passive electromagnetic shielding units are spaced uniformly, and a discrete source is located at the center of the ultra-wideband passive electromagnetic shielding surface. When the electromagnetic wave incident angle increases to 65°, the electromagnetic wave reflection coefficient of the ultra-wideband passive electromagnetic shielding unit operating at different incident angles is less than 10dB, and the electromagnetic wave absorption performance is greater than 90%. The structural parameters of the present invention are simple and adjustable, and electromagnetic shielding surfaces operating at other frequencies can be obtained by adjusting the parameters using the same design method, thereby achieving effective operation in other frequency ranges. The materials used in the present invention are all common materials, which are easy to scale up and have the advantages of being passive, easy to process, and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic shielding surfaces, in particular to an ultra-wideband passive electromagnetic shielding surface based on Kramers-Kronig relationship. Background Art

[0002] With the rapid development of electronic information technology, the application of various electronic and electrical equipment has become increasingly widespread. While bringing convenience to people's production and life, it has also brought serious problems such as electromagnetic radiation and electromagnetic interference. As an effective solution for electromagnetic shielding, electromagnetic shielding surfaces have been widely developed because they can effectively absorb electromagnetic waves entering the shielding material.

[0003] Traditional electromagnetic shielding surfaces typically require a significant thickness to achieve broadband absorption. For example, the pyramidal absorbers commonly used in electromagnetic shielding rooms typically exceed 30 mm in thickness to achieve far-field electromagnetic shielding. Their effectiveness deteriorates significantly as the incident angle of the electromagnetic wave increases. The rapid development of electromagnetic metamaterials in recent years has provided a viable approach to the realization of ultra-broadband passive electromagnetic shielding surfaces. Metamaterial structural units consist of a periodic arrangement of subwavelength-scale artificial resonant units. The effective permittivity and permeability of these units can be manipulated by artificially controlling the structural parameters of the units, providing a viable approach to achieving desired dispersion responses. However, the electromagnetic properties of metamaterials stem from the strong dispersion in the absorption resonance region, which is inevitably accompanied by significant losses and a narrow operating frequency band. To broaden the electromagnetic absorption band, multi-layer metamaterials and metamaterials with nested multi-sized metal patterns have been extensively studied. However, multi-layer metamaterial absorbers are relatively thick, and the absorption peaks of metamaterials with nested multi-sized metal patterns are severely coupled, resulting in only a limited expansion of the operating frequency band due to their limited size. Summary of the Invention

[0004] In order to solve the problems of large loss and narrow operating frequency of traditional metamaterial structural units, the purpose of the present invention is to provide a passive, low-cost, wide-operating frequency range, high-performance ultra-wideband passive electromagnetic shielding surface based on the Kramers-Kronig relationship.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: an ultra-wideband passive electromagnetic shielding surface based on the Kramers-Kronig relationship, comprising a plurality of ultra-wideband passive electromagnetic shielding units, wherein the plurality of ultra-wideband passive electromagnetic shielding units are arranged according to the incident angle of the radiated electromagnetic wave to form an ultra-wideband passive electromagnetic shielding surface, the spacing between the ultra-wideband passive electromagnetic shielding units is the same, and the discrete source is located at the center of the ultra-wideband passive electromagnetic shielding surface.

[0006] The ultra-wideband passive electromagnetic shielding unit includes a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a metal pattern, and a metal grounding layer. The first dielectric substrate and the second dielectric substrate are placed horizontally, the first dielectric substrate is located above the second dielectric substrate, and the third dielectric substrate is sandwiched between the first dielectric substrate and the second dielectric substrate. The board surface of the third dielectric substrate is perpendicular to the board surfaces of the first dielectric substrate and the second dielectric substrate. The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate together form an I-shape. The metal pattern is printed on a side board surface of the third dielectric substrate. The metal grounding layer forms the back surface. The metal grounding layer is used to connect the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate. The plane where the metal grounding layer is located is perpendicular to the board surfaces of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate.

[0007] When the incident angle of the electromagnetic wave increases to 65°, the electromagnetic wave reflection coefficient of the ultra-wideband passive electromagnetic shielding unit working at different incident angles is all below -10dB, the electromagnetic wave absorption performance is all above 90%, and the absorption bandwidth remains approximately stable.

[0008] The ultra-wideband passive electromagnetic shielding surface has an operating frequency range of 8 GHz to 12 GHz, a relative bandwidth of 40%, and achieves near-perfect absorption of electromagnetic waves within a 4 GHz bandwidth.

[0009] The metal pattern is roughly in the shape of a ring, with two parallel lines extending inward from an opening on one side of the ring. The two parallel lines are of the same length, and a resistor R is welded between the two parallel lines. For a given discrete source, an ultra-wideband passive electromagnetic shielding unit operating at different incident angles is obtained by adjusting the resistance value of the resistor R and the structural parameters of the metal pattern. The structural parameters of the metal pattern include r, m, n and t, where r is the inner diameter of the ring, m is the distance between the two parallel lines, the width of the ring and the line width of the two parallel lines are both n, and t is the length of the two parallel lines.

[0010] The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all made of Rogers low-loss plate. The dielectric constants of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all 4.64, and the loss tangents of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all 0.015. The metal ground layer is a copper plate with a thickness of 0.018 mm.

[0011] It can be seen from the above technical solution that the beneficial effects of the present invention are: first, in the ultra-wideband passive electromagnetic shielding unit of the present invention, when the electromagnetic wave incident angle increases to 65°, the electromagnetic wave reflection coefficient of the unit working at different incident angles is all below -10dB, and the electromagnetic wave absorption performance is all above 90%; second, for a given discrete source, the present invention arranges the above-mentioned units according to the discrete source radiation incident angle, thereby realizing an ultra-wideband passive electromagnetic shielding surface, the surface operating frequency range is 8GHz to 12GHz, the relative bandwidth is 40%, and it can achieve near-perfect absorption of electromagnetic waves within the 4GHz bandwidth range, providing a feasible idea for realizing ideal electromagnetic shielding of discrete sources; third, the unit structure of the present invention is uniform and unified, and the various structural parameters are simply adjustable. The electromagnetic shielding surfaces working at other frequencies can be obtained by adjusting the parameters by the same design method to achieve effective operation in other frequency ranges; fourth, the materials used in the present invention are all common materials, which are easy to expand on a large scale and have the advantages of being passive, easy to process and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention;

[0013] Figure 2 It is a structural schematic diagram of the ultra-wideband passive electromagnetic shielding unit in the present invention;

[0014] Figure 3 It is a schematic structural diagram of the metal pattern in the present invention;

[0015] Figure 4 It is the reflection parameter simulation result of the ultra-wideband passive electromagnetic shielding unit of the present invention working at different incident angles;

[0016] Figure 5 This is the electric field distribution diagram of the present invention under the condition of a given discrete source and a frequency of 8 GHz;

[0017] Figure 6 This is the electric field distribution diagram of the present invention under the condition of a given discrete source and a frequency of 10 GHz.

[0018] Figure 7 This is the electric field distribution diagram of the present invention under the condition of a given discrete source and a frequency of 12 GHz. DETAILED DESCRIPTION

[0019] like Figure 1 As shown, an ultra-wideband passive electromagnetic shielding surface based on the Kramers-Kronig relationship includes a plurality of ultra-wideband passive electromagnetic shielding units 8. The plurality of ultra-wideband passive electromagnetic shielding units 8 are arranged according to the incident angle of the radiated electromagnetic wave to form an ultra-wideband passive electromagnetic shielding surface 1. The spacing between the ultra-wideband passive electromagnetic shielding units 8 is the same, and the discrete source 2 is located at the center of the ultra-wideband passive electromagnetic shielding surface 1.

[0020] like Figure 2 As shown, the ultra-wideband passive electromagnetic shielding unit 8 includes a first dielectric substrate 3, a second dielectric substrate 4, a third dielectric substrate 5, a metal pattern 6, and a metal grounding layer 7. The first dielectric substrate 3 and the second dielectric substrate 4 are placed horizontally, with the first dielectric substrate 3 located above the second dielectric substrate 4. The third dielectric substrate 5 is sandwiched between the first dielectric substrate 3 and the second dielectric substrate 4. The surface of the third dielectric substrate 5 is perpendicular to the surfaces of the first dielectric substrate 3 and the second dielectric substrate 4. The first dielectric substrate 3, the second dielectric substrate 4, and the third dielectric substrate 5 together form an I-shape. The metal pattern 6 is printed on one side of the third dielectric substrate 5. The metal grounding layer 7 forms the back surface. The metal grounding layer 7 is used to connect the first dielectric substrate 3, the second dielectric substrate 4, and the third dielectric substrate 5. The plane where the metal grounding layer 7 is located is perpendicular to the surfaces of the first dielectric substrate 3, the second dielectric substrate 4, and the third dielectric substrate 5. The first dielectric substrate 3, the second dielectric substrate 4, and the third dielectric substrate 5 are all made of Rogers low-loss plate. The dielectric constants of the first dielectric substrate 3, the second dielectric substrate 4, and the third dielectric substrate 5 are all 4.64, and the loss tangents of the first dielectric substrate 3, the second dielectric substrate 4, and the third dielectric substrate 5 are all 0.015. The metal ground layer 7 is made of a copper plate with a thickness of 0.018 mm. Since the constitutive parameters of the ultra-wideband passive electromagnetic shielding unit 8, namely the dielectric constant and the magnetic permeability, satisfy the Krammers-Kronig relationship, this means that the real and imaginary parts of the constitutive parameters are mutually constrained. Therefore, if the imaginary (or real) part of the constitutive parameter is controlled, the real (or imaginary) part of the constitutive parameter can be correspondingly controlled. Based on the above principle, multiple resonances are introduced, and a lumped parameter element, namely a resistor R, is introduced into the resonant unit metal pattern 6. By changing the resistance value of the resistor R, the purpose of regulating the operating bandwidth of the ultra-wideband passive electromagnetic shielding unit 8 is achieved.

[0021] As the electromagnetic wave incident angle increases to 65°, the electromagnetic wave reflection coefficient of the ultra-wideband passive electromagnetic shielding unit 8 operating at different incident angles remains below -10dB, the electromagnetic wave absorption performance exceeds 90%, and the absorption bandwidth remains approximately stable. The ultra-wideband passive electromagnetic shielding surface 1 operates in the frequency range of 8GHz to 12GHz, with a relative bandwidth of 40%, achieving near-perfect electromagnetic wave absorption within a 4GHz bandwidth.

[0022] like Figure 3As shown, the metal pattern 6 is roughly in the shape of a ring, with two parallel lines 9 extending inward from an opening on one side of the ring. The two parallel lines 9 have the same length, and a resistor R is welded between the two parallel lines 9. For a given discrete source 2, by adjusting the resistance value of the resistor R and the structural parameters of the metal pattern 6, an ultra-wideband passive electromagnetic shielding unit 8 operating at different incident angles is obtained. The structural parameters of the metal pattern 6 include r, m, n and t, where r is the inner diameter of the ring, m is the distance between the two parallel lines 9, the width of the ring and the line width of the two parallel lines 9 are both n, and t is the length of the two parallel lines 9.

[0023] By adjusting the resistance value of the resistor R and the structure of the metal pattern 6, the dispersion of the equivalent constitutive parameters of the unit at different incident angles is precisely controlled, and the ultra-wideband passive electromagnetic shielding unit 8 working at different incident angles is obtained. The specific parameter data are shown in Table 1. Figure 1 As shown, for a given discrete source, its position is defined as (0, 0), the vertical distance from the electromagnetic wave radiated by the discrete source to the ultra-wideband passive electromagnetic shielding surface 1 is d, the unit with a vertical distance d from the discrete source, that is, the position (d, 0), is defined as 0° unit U1, the incident angle of 5° for the electromagnetic wave radiated by the discrete source on the shielding surface is unit U2, and U3, U4, U5...U15 are defined by analogy for each increase of 5°. The ultra-wideband passive electromagnetic shielding surface 1 is composed of the above-mentioned ultra-wideband passive electromagnetic shielding units 8 arranged according to the incident angle of the electromagnetic wave radiated by the given discrete source.

[0024] Table 1 Parameters of ultra-wideband passive electromagnetic shielding units working at different incident angles

[0025]

[0026] In order to verify the sensitivity of the ultra-wideband passive electromagnetic shielding surface 1 to the incident angle, the ultra-wideband passive electromagnetic shielding unit 8 is simulated and optimized based on the electromagnetic simulation software CST. Figure 4 It can be seen that when the frequency is between 8 GHz and 12 GHz and the electromagnetic wave incident angle increases from 0° to 65°, the electromagnetic wave reflection coefficient of the ultra-wideband passive electromagnetic shielding surface 1 is below -10 dB, and its electromagnetic wave absorption performance is above 90%, that is, the ultra-wideband passive electromagnetic shielding surface 1 can also effectively absorb electromagnetic waves when the electromagnetic waves are obliquely incident.

[0027] For a given discrete source 2, the electric field distribution obtained by simulation at frequencies of 8 GHz, 10 GHz and 12 GHz is shown in FIG. Figure 5 、 Figure 6 and Figure 7As shown in the figure, the absorption effect varies at different frequencies. Obviously, the absorption effect is the best at 8 GHz. However, at all frequencies, almost no electromagnetic waves penetrate the absorbing surface, the electric field distribution is relatively flat, and there is no obvious standing wave effect. Therefore, the constructed ultra-wideband passive electromagnetic shielding surface 1 can achieve good shielding effect against electromagnetic waves radiated in the near field of a given discrete source 2.

[0028] The ultra-wideband passive electromagnetic shielding unit 8 has a uniform and unified structure, and the materials used are all common materials, which are easy to expand on a large scale. It has the advantages of being passive, easy to process, and low-cost.

[0029] To sum up, the ultra-wideband passive electromagnetic shielding unit 8 of the present invention has an electromagnetic wave reflection coefficient of the unit working at different incident angles below -10dB when the electromagnetic wave incident angle increases to 65°, and the electromagnetic wave absorption performance is above 90%; for a given discrete source 2, the present invention arranges the above-mentioned units according to the radiation incident angle of the discrete source 2, thereby realizing an ultra-wideband passive electromagnetic shielding surface, the operating frequency range of the surface is 8GHz to 12GHz, the relative bandwidth is 40%, and it can achieve near-perfect absorption of electromagnetic waves within a bandwidth range of 4GHz, providing a feasible idea for realizing ideal electromagnetic shielding of discrete sources; the unit structure of the present invention is uniform and unified, and the various structural parameters are simple and adjustable. The electromagnetic shielding surfaces working at other frequencies can be obtained by adjusting the parameters by the same design method to achieve effective operation in other frequency ranges; the materials used in the present invention are all common materials, which are easy to expand on a large scale and have the advantages of being passive, easy to process and low cost.

[0030] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An ultra-wideband passive electromagnetic shielding surface based on the Kramers-Kronig relationship, characterized by: The invention comprises a plurality of ultra-wideband passive electromagnetic shielding units (8), wherein the plurality of ultra-wideband passive electromagnetic shielding units (8) are arranged according to the incident angle of the radiated electromagnetic wave to form an ultra-wideband passive electromagnetic shielding surface (1), the ultra-wideband passive electromagnetic shielding units (8) are spaced at the same distance from each other, and the discrete source (2) is located at the center of the ultra-wideband passive electromagnetic shielding surface (1); The ultra-wideband passive electromagnetic shielding unit (8) comprises a first dielectric substrate (3), a second dielectric substrate (4), a third dielectric substrate (5), a metal pattern (6) and a metal grounding layer (7), wherein the first dielectric substrate (3) and the second dielectric substrate (4) are placed horizontally, the first dielectric substrate (3) is located above the second dielectric substrate (4), the third dielectric substrate (5) is sandwiched between the first dielectric substrate (3) and the second dielectric substrate (4), the plate surface of the third dielectric substrate (5) is perpendicular to the plate surfaces of the first dielectric substrate (3) and the second dielectric substrate (4), the first dielectric substrate (3), the second dielectric substrate (4) and the third dielectric substrate (5) together form an I-shape, the metal pattern (6) is printed on one side plate surface of the third dielectric substrate (5), the metal grounding layer (7) forms the back surface, the metal grounding layer (7) is used to connect the first dielectric substrate (3), the second dielectric substrate (4) and the third dielectric substrate (5), and the plane where the metal grounding layer (7) is located is perpendicular to the plate surfaces of the first dielectric substrate (3), the second dielectric substrate (4) and the third dielectric substrate (5); The metal pattern (6) is roughly in the shape of a ring, and two parallel lines (9) are extended inward from an opening on one side of the ring. The two parallel lines (9) have the same length, and a resistor R is welded between the two parallel lines (9). For a given discrete source (2), by adjusting the resistance value of the resistor R and the structural parameters of the metal pattern (6), an ultra-wideband passive electromagnetic shielding unit (8) operating at different incident angles is obtained. The structural parameters of the metal pattern (6) include r, m, n and t, wherein r is the inner diameter of the ring, m is the distance between the two parallel lines (9), the width of the ring and the line width of the two parallel lines (9) are both n, and t is the length of the two parallel lines (9).

2. The ultra-wideband passive electromagnetic shielding surface based on the Kramers-Kronig relationship according to claim 1, characterized in that: When the incident angle of the electromagnetic wave increases to 65°, the electromagnetic wave reflection coefficient of the ultra-wideband passive electromagnetic shielding unit (8) working at different incident angles is all below -10dB, the electromagnetic wave absorption performance is all above 90%, and the absorption bandwidth remains approximately stable.

3. The ultra-wideband passive electromagnetic shielding surface based on the Kramers-Kronig relationship according to claim 1, characterized in that: The ultra-wideband passive electromagnetic shielding surface (1) has an operating frequency range of 8 GHz to 12 GHz, a relative bandwidth of 40%, and achieves near-perfect absorption of electromagnetic waves within a 4 GHz bandwidth.

4. The ultra-wideband passive electromagnetic shielding surface based on the Kramers-Kronig relationship according to claim 1, characterized in that: The first dielectric substrate (3), the second dielectric substrate (4), and the third dielectric substrate (5) all adopt Rogers low-loss plate materials, the dielectric constants of the first dielectric substrate (3), the second dielectric substrate (4), and the third dielectric substrate (5) are all 4.64, and the loss tangents of the first dielectric substrate (3), the second dielectric substrate (4), and the third dielectric substrate (5) are all 0.015; the metal grounding layer (7) adopts a copper plate with a thickness of 0.018 mm.

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