Resonant cavity based on hollow square pattern

Abstract

The invention discloses a resonant cavity based on a hollow square pattern, and particularly relates to the technical field of metasurface electromagnetic shielding, and the hollow square pattern of the resonant cavity is characterized in that squares with the side length of L2 are removed from four corners or four sides of a square with the side length of L1; a specific pattern is removed from the centroid of the square; the specific pattern is composed of a plurality of same basic patterns; wherein one basic pattern is located at the center of the specific pattern, and the four vertexes of the basic pattern coincide with the vertexes of the other basic patterns.

Description

Technical Field

[0001] The present invention relates to the technical field of metasurface electromagnetic shielding, and in particular to a resonant cavity based on a hollow square pattern. Background Art

[0002] Terahertz (THz) waves are electromagnetic waves with a frequency band of approximately 0.1-10 THz. With the continuous development of emerging terahertz science and technology, new applications have been extended to include broadband communications, radar detection, medical imaging, non-destructive testing, safety inspections, etc. Given the richness of frequency information contained in the terahertz band, its unique spectral characteristics make this band show significant advantages in accurately detecting tiny targets. Therefore, it has become a vital research task to develop resonant devices designed specifically for the terahertz band to fully utilize its high-frequency characteristics. Terahertz resonant devices based on metasurfaces are a type of device that can effectively regulate electromagnetic waves and make them available for subsequent processes. By designing the metasurface structure of terahertz resonant devices, precise control of electromagnetic waves can be achieved.

[0003] Metasurface is a new type of artificially designed material. As a two-dimensional form of metamaterial, it is composed of a large number of periodically arranged subwavelength-scale unit structures, which can precisely control the propagation characteristics of electromagnetic waves, such as reflection, refraction, polarization and phase. The emergence of metasurfaces provides unprecedented flexibility and precision for the manipulation of electromagnetic waves, giving it broad application prospects in antenna design, sensors and stealth technology. With the advancement of materials science and micro-nano manufacturing technology, the design and manufacture of metasurfaces have become more feasible, providing possibilities for the practical application of metasurfaces. Terahertz resonant devices made of metasurfaces can convert incident terahertz energy into other energy losses by exciting localized surface plasmon resonance on the surface of the material, thereby achieving precise manipulation of terahertz waves.

[0004] In summary, current practical applications urgently need to carry out research on terahertz resonant devices that can achieve dual-band terahertz absorption and broadband terahertz absorption, so that they can be applied to terahertz non-destructive testing, energy harvesting, and super-resolution imaging. Summary of the invention

[0005] To this end, the present invention provides a resonant cavity based on a hollow square pattern to achieve broadband terahertz resonant absorption in specific dual-bands to solve the problems raised in the background technology.

[0006] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions: a resonant cavity based on a hollow square pattern, wherein the hollow square pattern of the resonant cavity is obtained by removing squares with a side length of L2 from the four corners or on the four sides of a square with a side length of L1, and removing a specific pattern at the centroid of the square; the specific pattern is composed of a plurality of identical basic patterns; one of the basic patterns is located at the center of the specific pattern, and the four vertices of the basic pattern coincide with a vertex of the remaining plurality of basic patterns.

[0007] Preferably, the hollow square pattern of the resonant cavity is obtained by removing a square with a side length of L1 from its four corners and a square with a side length of L2 from the midpoints of the four sides, and removing a specific pattern at the centroid of the square; the specific pattern is composed of several identical basic patterns; the basic pattern is a square with a side length of L3.

[0008] Preferably, the hollow square pattern of the resonant cavity is obtained by removing a square with a side length of L1 from its four corners and a square with a side length of L2 from the midpoints of the four sides, and removing a specific pattern at the centroid of the square; the specific pattern is composed of several identical basic patterns; the basic pattern is a regular octagon with a side length of L4.

[0009] Preferably, the hollow square pattern of the resonant cavity is obtained by removing one square with a side length of L1 from its four corners and multiple squares with a side length of D at equal intervals on the four sides, and removing a specific pattern at the centroid of the square; the specific pattern is composed of several identical basic patterns; the basic pattern is a square with a side length of L3.

[0010] Preferably, the hollow square pattern of the resonant cavity is obtained by removing a plurality of squares with a side length of D at equal intervals on the four sides of a square with a side length of L1, and removing a specific pattern at the centroid of the square; the specific pattern is composed of several identical basic patterns; the basic pattern is a square with a side length of L3.

[0011] Preferably, the metasurface is composed of a periodic array of a plurality of two-dimensionally sequentially arranged hollow square patterns.

[0012] Preferably, the resonant cavity is composed of a reflective bottom plate, an intermediate dielectric layer, a metasurface and a top dielectric layer which are sequentially attached from bottom to top.

[0013] Preferably, the reflective bottom plate is a conductive film with a thickness of 0.15 μm and a surface resistance of 8 Ω / sq.

[0014] Preferably, the middle dielectric layer and the top dielectric layer are both FEP films with a thickness of 10 μm and a dielectric constant of 2.1.

[0015] Preferably, the metasurface is prepared by patterning a conductive film with a thickness of 0.15 μm and a surface resistance of 120 Ω / sq.

[0016] The present invention has the following advantages:

[0017] 1. The present invention proposes a resonant cavity based on a hollow square pattern composed of a four-layer structure of a reflective bottom plate, an intermediate dielectric layer, a metasurface and a top dielectric layer. The structure is simple and easy to prepare.

[0018] 2. The metasurface of the present invention is composed of an array of hollow square patterns, which can enable the terahertz resonant cavity to achieve more than 90% terahertz resonance absorption effect in the dual terahertz frequency bands of 2.38-4.57THz and 6.05-7.90THz at the same time, and has dual-band terahertz resonance absorption effect and broadband terahertz resonance absorption effect.

[0019] In summary, the present invention can realize dual-band terahertz resonance absorption and broadband terahertz resonance absorption, has the characteristics of simple structure and easy preparation, and can be applied to the fields of terahertz non-destructive testing, energy collection and super-resolution imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front view of the hollow square pattern of comparative example 1;

[0021] Figure 2 is a periodic array diagram of the metasurface of comparative example 1;

[0022] Figure 3 is a curve diagram of electromagnetic wave resonance absorption characteristics of the resonant cavity of comparative example 1 in the terahertz band;

[0023] Figure 4 It is a front view of the hollow square pattern of comparative example 2;

[0024] Figure 5 is a periodic array diagram of the metasurface of comparative example 2;

[0025] Figure 6 is a graph showing the electromagnetic wave resonance absorption characteristics of the resonant cavity of comparative example 2 in the terahertz band;

[0026] Figure 7 It is a front view of the hollow square pattern of comparative example 3;

[0027] Figure 8 is a periodic array diagram of the metasurface of comparative example 3;

[0028] Fig. 9 is a graph showing the electromagnetic wave resonance absorption characteristics of the resonant cavity of comparative example 3 in the terahertz band;

[0029] Fig.10 Schematic diagram of the three-dimensional structure of the resonant cavity based on the hollow square pattern of the first embodiment;

[0030] Fig.11 It is a front view based on the hollow square pattern of the first embodiment;

[0031] Fig.12 This is a periodic array diagram based on a hollow square pattern metasurface of Example 1;

[0032] Fig.13 This is a graph showing the electromagnetic wave resonance absorption characteristics of the resonant cavity based on the hollow square pattern in the terahertz band according to the first embodiment;

[0033] Fig.14 The hollow square pattern of the second embodiment is combined with other patterns to form a new periodic array diagram;

[0034] Fig.15 A curve diagram of electromagnetic wave resonance absorption characteristics in the terahertz band when the hollow square pattern of Example 2 is combined with other patterns to form a new periodic array;

[0035] In the figure: 1. Reflective base plate; 2. Middle dielectric layer; 3. Metasurface; 4. Top dielectric layer. DETAILED DESCRIPTION

[0036] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Comparative Example 1: Figure 1 As shown, the resonant cavity of the metasurface is a square with a side length of L1, obtained by removing squares with a side length of L2 at the four corners and the midpoints of the four sides, and removing an octagonal specific pattern at the centroid of the square. The center of the specific pattern has a regular octagon X with a side length of L4, and the upper left, lower left, upper right, and lower right thereof each have a regular octagon X with the same side length of L4. These five identical regular octagons X are combined to form the specific pattern. In this comparative example, L4=9.8μm.

[0038] Figure 2 The metasurface is Figure 1It is basically composed of a periodic array of several two-dimensionally arranged hollow square patterns.

[0039] Figure 3 The CST Microwave Studio uses the resonant cavity simulation test results of the pattern described in this comparative example. This comparative example achieves more than 90% terahertz resonance absorption effect simultaneously in the dual terahertz frequency bands of 2.40-4.52THz and 6.05-7.91THz.

[0040] Comparative Example 2: Figure 4 As shown, the resonant cavity of the metasurface is a square with a side length of L1, which is obtained by removing a number of squares with a side length of D at intervals of length D on the four corners and four sides, and removing a specific pattern at the centroid of the square; the center of the specific pattern has a square Y with a side length of L3, and the four vertices of the square Y each coincide with a vertex of a square Y with the same side length of L3, and these five identical squares Y are combined to form a specific pattern, and D=7.5μm in this comparative example.

[0041] Figure 5 The metasurface is Figure 4 It is basically composed of a periodic array of several two-dimensionally arranged hollow square patterns.

[0042] Figure 6 The CST Microwave Studio uses the resonant cavity simulation test results of the pattern described in this comparative example. This comparative example achieves more than 90% terahertz resonance absorption effect simultaneously in the dual terahertz frequency bands of 2.64-3.84THz and 6.14-7.76THz.

[0043] Comparative Example 3: Figure 7 As shown, the resonant cavity of the metasurface is a square with a side length of L1, which is obtained by removing a number of squares with a side length of D at intervals of length D on the four sides, and removing a specific pattern at the centroid of the square; the center of the specific pattern has a square Z with a side length of L3, and the four vertices of the square Z each coincide with a vertex of a square Z with the same side length of L3, and these five squares Z are combined to form a specific pattern, and D=7.5μm in this comparative example.

[0044] Figure 8 The metasurface is Figure 7 It is basically composed of a periodic array of several two-dimensionally arranged hollow square patterns.

[0045] Fig. 9The CST Microwave Studio uses the resonant cavity simulation test results of the pattern described in this comparative example. This comparative example achieves more than 90% terahertz resonance absorption effect simultaneously in the three terahertz frequency bands of 2.64-3.84THz, 6.12-6.74THz and 6.80-7.79THz.

[0046] Embodiment 1: Fig.11 As shown, this embodiment proposes a resonant cavity based on a hollow square pattern, wherein the hollow square pattern of the resonant cavity is obtained by removing squares with a side length of L2 from the four corners and the midpoints of the four sides of a square with a side length of L1, and removing a specific pattern at the centroid of the square; the specific pattern is composed of square A, square B1, square B2, square B3 and square B4; at the center of the specific pattern, there is a square A with a side length of L3, and its four vertices each coincide with a vertex of square B1, square B2, square B3 and square B4.

[0047] The four sides of the square A at the center of the specific pattern, and the four sides of the squares B1, B2, B3 and B4 are all parallel to the four sides of the hollow square pattern.

[0048] like Fig.10 As shown, the resonant cavity is composed of a reflective bottom plate 1, an intermediate dielectric layer 2, a metasurface 3 and a top dielectric layer 4 which are sequentially attached from bottom to top.

[0049] exist Fig.11 On the basis of, the metasurface is composed of a periodic array of several two-dimensionally arranged hollow square patterns, such as Fig.12 shown.

[0050] Embodiment 2: Based on Embodiment 1, the hollow square pattern is further arranged and combined with other patterns to form a more complex periodic array metasurface, such as Fig.14 shown.

[0051] Fig.15 Based on the simulation test results of CST Microwave Studio on the metasurface in which the hollow square pattern is arranged and combined with other patterns to form a more complex periodic array, this embodiment achieves more than 90% terahertz resonance absorption effect simultaneously in the dual terahertz frequency bands of 2.39-4.56THz and 6.05-7.87THz.

[0052] and Fig.13 (Example 1) Compared with Fig.15The total terahertz absorption bandwidth of the combined array of (Example 2) is 3.99 THz, and the total terahertz absorption bandwidth of Example 1 is 4.04 THz. Therefore, Example 1 can achieve a terahertz resonance absorption effect of more than 90% in a wider terahertz frequency band.

[0053] The reflective bottom plate 1 is a conductive film with a thickness of 0.15 μm and a surface resistance of 8 Ω / sq.

[0054] The middle dielectric layer 2 and the top dielectric layer 4 are both FEP films with a thickness of 10 μm and a dielectric constant of 2.1.

[0055] The metasurface 3 is a conductive film with a thickness of 0.15 μm and a surface resistance of 120 Ω / sq.

[0056] The above-mentioned resonant cavity based on the hollow square pattern, in this embodiment, the periodic array period of the metasurface of the resonant cavity is x=150μm, and the other structural parameters are: L1=112.5μm, L2=9μm, L3=23.6μm.

[0057] like Fig.13 As shown, the CST Microwave Studio was used to simulate and test the resonant cavity based on the hollow square pattern, and more than 90% of the terahertz resonance absorption effect was achieved simultaneously in the dual terahertz frequency bands of 2.38-4.57THz and 6.05-7.90THz, with dual-band terahertz resonance absorption effect and broadband terahertz resonance absorption effect.

[0058] The method for preparing a resonant cavity based on a hollow square pattern in the above-mentioned embodiment is as follows: after etching the above-mentioned hollow square pattern on a conductive film by laser etching, the material in the redundant structural area is removed, and what remains is a metasurface, and then a resonant device based on a hollow square pattern is obtained by bonding the reflective bottom plate 1, the middle dielectric layer 2, the metasurface 3 and the top dielectric layer 4 in the order from bottom to top.

[0059] In summary, compared with comparative example 1, the total terahertz absorption bandwidth of comparative example 1 is 3.98 THz, and the total terahertz absorption bandwidth of embodiment 1 is 4.04 THz. Therefore, embodiment 1 can achieve more than 90% terahertz resonance absorption effect in a wider terahertz frequency band.

[0060] Compared with comparative example 2, the total terahertz absorption bandwidth of comparative example 2 is 2.82 THz, while the total terahertz absorption bandwidth of embodiment 1 is 4.04 THz. Therefore, embodiment 1 can achieve a terahertz resonance absorption effect of more than 90% in a wider terahertz frequency band.

[0061] Compared with comparative example 3, the total terahertz absorption bandwidth of comparative example 3 is 2.81 THz, while the total terahertz absorption bandwidth of embodiment 1 is 4.04 THz. Therefore, embodiment 1 can achieve a terahertz resonance absorption effect of more than 90% in a wider terahertz frequency band.

[0062] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A resonant cavity based on a hollow square pattern, characterized in that: The hollow square pattern of the resonant cavity is obtained by removing squares with a side length of L2 from the four corners or on the four sides of a square with a side length of L1, and removing a specific pattern at the centroid of the square; the specific pattern is composed of several identical basic patterns; one of the basic patterns is located at the center of the specific pattern, and the four vertices of the basic pattern coincide with one vertex of the other multiple basic patterns.

2. A resonant cavity based on a hollow square pattern according to claim 1, characterized in that: The hollow square pattern of the resonant cavity is obtained by removing one square with a side length of L1 from its four corners, removing a square with a side length of L2 from the midpoints of the four sides, and removing a specific pattern at the centroid of the square; the specific pattern is composed of several identical basic patterns; the basic pattern is a square with a side length of L3.

3. A resonant cavity based on a hollow square pattern according to claim 1 or 2, characterized in that: The hollow square pattern of the resonant cavity is obtained by removing one square with a side length of L1 from its four corners, removing a square with a side length of L2 from the midpoints of the four sides, and removing a specific pattern from the centroid of the square; the specific pattern is composed of several identical basic patterns; the basic pattern is a regular octagon with a side length of L4.

4. A resonant cavity based on a hollow square pattern according to claim 1, characterized in that: The hollow square pattern of the resonant cavity is obtained by removing one square with a side length of L1 from its four corners and multiple squares with a side length of D at equal intervals on the four sides, and removing a specific pattern at the centroid of the square; the specific pattern is composed of several identical basic patterns; the basic pattern is a square with a side length of L3.

5. The resonant cavity based on the hollow square pattern according to claim 1, characterized in that: The hollow square pattern of the resonant cavity is obtained by removing multiple squares with a side length of D at equal intervals on the four sides of a square with a side length of L1, and removing a specific pattern at the centroid of the square; the specific pattern is composed of several identical basic patterns; the basic pattern is a square with a side length of L3.

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