High-performance, integrated all-ceramic metamaterial perfect absorber

Abstract

The present invention discloses a high-performance, integrated all-ceramic-based metamaterial perfect absorber. The ceramic-based metamaterial absorber has a simple and compact structure and is highly compatible with different dielectric ceramic systems to obtain perfect absorption characteristics at different frequencies. It does not require a substrate and can be integrated and matched with a variety of microwave / millimeter wave devices and systems, breaking the theoretical framework of traditional construction of perfect absorption devices. The absorber includes a ceramic resonant unit array, and the ceramic resonant unit array includes a number of ceramic resonant units distributed in a matrix. The ceramic resonant unit is composed of a temperature-stable dielectric ceramic with an orthogonal cubic structure. According to the equivalent circuit model, the expression of its equivalent resistance R is: #imgabs0# where Q is the inverse of the loss tangent value of the ceramic at the perfect absorption frequency; L is the length of the long side of the ceramic resonant unit; S is the cross-sectional area of ​​the ceramic resonant unit, S=h×r; ω is the perfect absorption frequency; ε0 is the vacuum dielectric constant; ε r is the relative dielectric constant of the ceramic.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and in particular relates to a high-performance, integrated all-ceramic-based metamaterial perfect absorber. Background Art

[0002] Metamaterial absorbers hold broad application prospects in areas such as solar energy absorption and conversion, microwave / millimeter-wave electromagnetic interference mitigation, detection, and imaging. In recent years, with the continuous development of functional ceramic materials, research on ceramic-based metamaterials has continued to surge. Compared to traditional metal-based metamaterials, which suffer from high losses (high ohmic losses), complex structures (multiple resonant structures), and inability to withstand high temperatures (often using polymer substrates), the rise of these metamaterials offers a new direction for the development of metamaterial absorbers and is expected to further promote the industrialization of metamaterial devices.

[0003] Currently, ceramic-based metamaterial absorbers are mainly divided into the following two categories:

[0004] 1. Based on Mie resonance theory and effective medium theory, metamaterial arrays are fabricated using oxide dielectric ceramics (such as TiO2, CaTiO3, and SrTiO3) with high dielectric constants (typically above 100). However, due to the single-mode absorption characteristics, large-area metal reflector structures are essential to achieve perfect absorption and improve efficiency. Consequently, the integration and process compatibility of these metamaterial absorbers still require further improvement, and the problem of poor temperature stability remains unresolved.

[0005] 2. Based on the plasma excitation mechanism, conductive ceramics (such as borides and nitrides) are used to prepare a "conductive ceramic-dielectric-conductive ceramic" sandwich structure metamaterial. In this case, the process matching requirements between the layers limit the material selection, creating a huge obstacle for its flexible design and hindering the stable realization of perfect absorption. In addition, changes in operating temperature often cause fluctuations in the conductivity of such materials, which significantly reduces the frequency-temperature stability of the metamaterial absorber and poor cycling performance (it is easily oxidized above 800°C).

[0006] To meet the diverse demands of practical applications, such as space exploration and aircraft engines in extremely high-temperature environments (often exceeding 1000°C), these ceramic-based metamaterial absorbers face common challenges, including relatively complex process structures, poor integration, and poor absorption stability, severely limiting their further application. This demonstrates the urgent need for breakthroughs in existing metamaterial design frameworks for high-performance, integrable metamaterial absorbers. Summary of the Invention

[0007] The present invention aims to provide a high-performance, integrated, all-ceramic metamaterial perfect absorber. This ceramic-based metamaterial absorber has a simple and compact structure and is highly compatible with various dielectric ceramic systems, achieving perfect absorption characteristics at different frequencies. Without requiring a substrate, it can be integrated with a variety of microwave / millimeter-wave devices and systems, breaking the traditional theoretical framework for constructing a perfect absorber.

[0008] like Figure 1 As shown, the high-performance, integrated all-ceramic-based metamaterial perfect absorber provided by the present invention includes a ceramic resonant unit array, and the ceramic resonant unit array includes a ceramic resonant unit 1; a plurality of ceramic resonant units 1 are distributed in a matrix.

[0009] According to one embodiment of the present invention, preferably, Figure 2 As shown, the ceramic resonant unit is composed of a temperature-stable dielectric ceramic with an orthogonal cubic structure. According to the equivalent circuit model, the expression of its equivalent resistance R is:

[0010]

[0011] Where Q is the inverse of the loss tangent of the ceramic at the perfect absorption frequency; L is the length of the long side of the ceramic resonant unit; S is the cross-sectional area of ​​the ceramic resonant unit, S = h × r, S = h × r, h is the height of the ceramic resonant unit, r is the length of the short side of the ceramic resonant unit; ω is the perfect absorption frequency; ε0 is the vacuum dielectric constant; ε r is the relative dielectric constant of the ceramic.

[0012] The Q value is measured by a network analyzer to obtain the Qf value of the ceramic material, and then the Q value of the ceramic material at the corresponding frequency is obtained based on the dispersion relationship. The Q value can be obtained by referring to conventional methods in the art.

[0013] ε0 is a constant, approximately 8.854187817×10 -12 F / m.

[0014] ω is calculated by comsol and then verified by measurement. The method for determining the ω value can be obtained by referring to conventional methods in the field.

[0015] After obtaining the appropriate R value, by adjusting the coupling distance d (such as Figure 3 As shown in Figure 2), the metamaterial period is L+d, which can induce the ceramic resonant unit array to obtain perfect absorption characteristics.

[0016] In the present invention, the relative dielectric constant ε of the ceramic material forming the ceramic resonator unit is r It can be 45-100, and the Qf value is 4000-10000GHz.

[0017] In the present invention, the coupling distance d can be adjusted within the range of 0.1-0.2 mm.

[0018] In a specific embodiment of the present invention, L=3.6 mm; h=1.125 mm, and r=1.57 mm.

[0019] In a specific embodiment of the present invention, the relative dielectric constant of the ceramic is set to 70, the quality factor Qf value is 6200 GHz (the Qf value of this type of ceramic is approximately constant in the microwave / millimeter wave frequency band), and d is 0.12 mm. The simulation results are as follows: Figure 4 Here, the temperature stability of perfect absorption is determined only by the dielectric properties of the ceramic material itself.

[0020] The R value described in the present invention is derived from the equivalence of material parameters and unit dimensions, which facilitates understanding of the physical process and has no practical significance. In the embodiment of the present invention, the equivalent resistance R is approximately 22806Ω.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The structure is simple and compact, and it is highly compatible with different dielectric ceramic systems to obtain perfect absorption characteristics at different frequencies. It does not require a substrate and can be integrated with a variety of microwave / millimeter wave devices and systems, breaking the traditional theoretical framework for constructing perfect absorption devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of the high-performance, integrated all-ceramic-based metamaterial perfect absorber provided by the present invention, wherein 1 is a ceramic resonant unit.

[0024] Figure 2 for Figure 1 Schematic diagram of the ceramic resonant unit shown in ; wherein, L is the length of the long side of the ceramic resonant unit, and S is the cross-sectional area of ​​the ceramic resonant unit (S=h×r).

[0025] Figure 3 Schematic diagram of the coupling state between ceramic resonant unit structures.

[0026] Figure 4 Simulation results of a high-performance, integrated all-ceramic metamaterial perfect absorber with L=3.6mm, h=1.125mm, r=1.57mm, d=0.12mm, a dielectric constant of 70, and a Qf value of 6200GHz. DETAILED DESCRIPTION

[0027] The present invention is further described below with reference to specific examples, but the present invention is not limited to the following examples. The methods described are conventional methods unless otherwise specified. The raw materials described can be obtained from public commercial channels unless otherwise specified.

[0028] Example 1: High-performance integrated all-ceramic metamaterial perfect absorber

[0029] like Figure 1 As shown, the high-performance, integrated all-ceramic-based metamaterial perfect absorber provided by the present invention includes a ceramic resonant unit array, which includes a ceramic resonant unit 1; a plurality of ceramic resonant units 1 are distributed in a matrix (such as an 8*8 matrix arrangement).

[0030] like Figure 2 As shown, the ceramic resonant unit is composed of a temperature-stable dielectric ceramic with an orthogonal cubic structure. According to the equivalent circuit model, the expression of its equivalent resistance R is:

[0031]

[0032] Where Q is the reciprocal of the loss tangent of the ceramic at the perfect absorption frequency; L is the length of the long side of the ceramic resonator unit, L = 3.6 mm; S is the cross-sectional area of ​​the ceramic resonator unit, S = h × r, h = 1.125 mm, r = 1.57 mm; ω is the perfect absorption frequency; ε0 is the dielectric constant of vacuum (which is a constant, approximately 8.854187817 × 10^ -12 F / m); ε r is the relative dielectric constant of the ceramic.

[0033] After obtaining the appropriate R value, by adjusting the coupling distance d (such as Figure 3 As shown in Figure 2), the metamaterial period is L+d, which can induce the ceramic resonant unit array to obtain perfect absorption characteristics.

[0034] In this embodiment, the relative dielectric constant ε of the ceramic is set r The Qf value is 70, the Qf value is 6200 GHz (the Qf value of this type of ceramic is approximately a constant in the microwave / millimeter wave frequency band), the derived Q value is about 207.36, the perfect absorption frequency is 29.9 GHz, and the calculated R value is about 22806 Ω.

[0035] In this embodiment, the relative dielectric constant ε of the ceramic is set r The Qf value is 70, the Qf value is 6200GHz (the Qf value of this type of ceramic is approximately constant in the microwave / millimeter wave frequency band), and d is 0.12mm. The simulation results are as follows Figure 4 Here, the temperature stability of perfect absorption is determined only by the dielectric properties of the ceramic material itself.

[0036] Depend on Figure 4 It can be seen that when the parameter requirements of this embodiment are met, the all-ceramic-based metamaterial of the present invention can achieve a perfect absorption effect (absorption rate>99%) at 29.9 GHz.

[0037] The above embodiments are only used to illustrate the present invention, wherein the ceramic materials and parameter settings are all subject to change. Any equivalent transformations and improvements based on the technical solution of the present invention should not be excluded from the protection scope of the present invention.

Claims

1. A high-performance, integrated, all-ceramic-based metamaterial perfect absorber, comprising a ceramic resonant unit array, wherein the ceramic resonant unit array comprises ceramic resonant units; the plurality of ceramic resonant units are distributed in a matrix; The ceramic resonant unit is composed of a temperature-stable dielectric ceramic with an orthogonal rectangular parallelepiped structure, and does not require a substrate. The length of the long side of the ceramic resonant unit is L = 3.6 mm; the height h = 1.125 mm, the length of the short side r = 1.57 mm, and the adjustable coupling spacing d is 0.1-0.2 mm. The adjustable coupling spacing is the distance between the cross section where the short side and height of the resonant unit are located and the cross section of the adjacent ceramic resonant unit.

2. The high-performance, integrable, all-ceramic-based metamaterial perfect absorber according to claim 1, characterized in that: According to the equivalent circuit model, the equivalent resistance R of the ceramic resonant unit is expressed as: Where Q is the inverse of the loss tangent of the ceramic at the perfect absorption frequency; L is the length of the long side of the ceramic resonator unit; S is the cross-sectional area of ​​the ceramic resonator unit, S = h × r, h is the height of the ceramic resonator unit, r is the length of the short side of the ceramic resonator unit; ω is the perfect absorption frequency; ε0 is the dielectric constant of vacuum; ε r is the relative dielectric constant of the ceramic.

3. The high-performance, integrable, all-ceramic-based metamaterial perfect absorber according to claim 2, characterized in that: The relative dielectric constant ε of the ceramic material forming the ceramic resonator unit r The value of the quality factor Qf of the ceramic material forming the ceramic resonance unit is 45-100, and the value of the quality factor Qf is 4000-10000 GHz; the value of Qf is the product of the quality factor Q and the resonance frequency f.

4. The high-performance, integrable, all-ceramic-based metamaterial perfect absorber according to claim 2, characterized in that: After obtaining the appropriate R value, by adjusting the coupling spacing d, the metamaterial period is L+d, which can induce the ceramic resonant unit array to obtain perfect absorption characteristics.

5. The high-performance, integrable, all-ceramic-based metamaterial perfect absorber according to claim 1, characterized in that: The coupling distance d is adjusted to 0.12 mm.

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