A Quasi-Double-Ring Frequency Selective Surface
By deforming the traditional two-side ring structure, a two-side ring frequency selection surface is designed, the internal structure controls the resonant frequency of the low-frequency stopband, and the external structure controls the resonant frequency of the high-frequency stopband, which solves the restricted adjustment of the resonant frequency in the traditional structure. The problem is to achieve the effect of independently controlling the dual-frequency stopband frequency.
Patent Information
- Application Number
- CN202211032827.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-08-26
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2042-08-26
AI Technical Summary
The traditional two-side ring frequency selection surface structure limits the designer's idea of adjusting the resonant frequency, causing designers to pay more attention to the resonant depth, bandwidth and angle stability, while ignoring the problem of how to independently adjust the resonant frequency of low-frequency and high-frequency stopbands.
A two-side ring frequency selection surface is designed. By deforming the traditional two-side ring structure, the internal structure controls the resonant frequency of the low-frequency stopband, while the external structure controls the resonant frequency of the high-frequency stopband, using a periodic structure, by M× N units are composed of the unit including nested deformation square ring internal and external structures, with extensions at the opening of the internal structure, and the opening width of the external structure is greater than the sum of the widths of the internal structure and extensions.
The internal structure independently controls the resonant frequency of the low-frequency stopband, and the external structure independently controls the resonant frequency of the high-frequency stopband, providing a different structure to control the resonant frequency of the dual-frequency stopband, expanding the designer's adjustment ideas.
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Figure CN115275629B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to microwave and communication devices, in particular to a double-ring-like frequency selective surface. Background Art
[0002] Due to its good frequency filtering ability, frequency selective surfaces are widely used in antenna covers, absorbers, radar cross-section reduction, etc. With the increase of communication frequency and the expansion of available frequency bands, frequency selective surfaces working in dual bands or multiple bands have attracted much attention. Among them, the traditional double-ring structure can be used as a dual-band band-stop filter. As we all know, the traditional double-ring frequency selective surface has two stopbands, and these two stopbands can be independently controlled: the external structure, i.e., the outer ring, independently controls the resonant frequency of the low-frequency stopband, and the internal structure, i.e., the inner ring, independently controls the resonant frequency of the high-frequency stopband. In other words, by changing the structural parameters of the external structure, i.e., the outer ring, the frequency of the low-frequency stopband will change, and by changing the structural parameters of the internal structure, i.e., the inner ring, the frequency of the high-frequency stopband will change. This characteristic is also in line with the law of electromagnetic fields and microwaves that "the resonant frequency is inversely proportional to the size of the structure": the internal structure is small in size, resulting in a high resonant frequency, and the external structure is large in size, resulting in a low resonant frequency.
[0003] However, this method of adjusting the resonant frequency limits the designer's thinking, making the designer think that the resonant frequency can only be adjusted in this way for a square ring. Therefore, most filters based on square rings only pursue the resonance depth, bandwidth and angle stability, while ignoring the issue of how to adjust the resonant frequency. Summary of the invention
[0004] Based on the above problems, how to improve and deform the double-ring structure so that its internal structure can control the resonant frequency of the low-frequency stopband and its external structure can control the resonant frequency of the high-frequency stopband has become an urgent problem to be solved in this field.
[0005] To achieve the above object, the present invention provides a quasi-double ring frequency selective surface, characterized in that: the filter is a periodic structure, including M×N units, adjacent units have no spacing, and M and N are both positive integers greater than or equal to 2;
[0006] The unit comprises a resonant layer and a substrate; along the wave incident direction, the resonant layer and the substrate are arranged in sequence;
[0007] The resonance layer is composed of an internal structure and an external structure nested together;
[0008] The internal structure and the external structure are two deformed square rings;
[0009] The internal structure is open on the four sides of the square ring, and there is an extension portion outside the square at the opening of each side; the external structure is open on the four sides of the square ring;
[0010] Each extension of the internal structure is rectangular, and the extension abuts against the edge of the unit;
[0011] The opening width of the outer structure is greater than the sum of the opening width of the inner structure and twice the rectangular width of the extension portion;
[0012] The centers of the internal structure and the external structure coincide with each other, and the line connecting the internal structure and the center of the substrate is perpendicular to the substrate and the resonance layer; the sides of the internal structure and the external structure are parallel to the sides corresponding to the substrate;
[0013] Optionally, the material of the resonance layer is any one of copper, gold and silver.
[0014] Optionally, the thickness of the resonance layer is in the range of 30-40 um.
[0015] Optionally, the material of the substrate is any one of polytetrafluoroethylene F4BM high-frequency antenna board, glass fiber epoxy resin material FR4, polyethylene terephthalate (PET), etc.
[0016] Compared with the prior art, the present invention has the following beneficial effects:
[0017] The present invention proposes a double-ring-like frequency selective surface, which deforms the traditional double-ring structure so that its internal structure controls the resonant frequency of the low-frequency stopband, while the external structure controls the resonant frequency of the high-frequency stopband. The present invention provides a different structure for controlling the resonant frequency of the dual-frequency stopband. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0019] Figure 1 This is a schematic diagram of the structure of a single unit of a double-ring frequency selective surface according to an embodiment of the present invention;
[0020] Figure 2 A side view of a single unit of a double-ring frequency selective surface according to an embodiment of the present invention;
[0021] Figure 3 This is a schematic diagram of the resonant layer structure of a single unit of a double-ring frequency selective surface according to an embodiment of the present invention;
[0022] Figure 4 This is a transmission response diagram of a double-ring frequency selective surface of an embodiment of the present invention when having external structures of different lengths;
[0023] Figure 5 It is a transmission response diagram of a double-ring frequency selective surface of an embodiment of the present invention with external structures having different widths;
[0024] Figure 6 It is a transmission response diagram of the double-ring frequency selective surface of the embodiment of the present invention when the internal structure has different opening lengths;
[0025] Figure 7 This is a transmission response diagram of a double-ring frequency selective surface according to an embodiment of the present invention when having extensions with different widths.
[0026] Among them, 1. resonance layer, 2. substrate, 3. external structure, 4. internal structure, 5. extension part. DETAILED DESCRIPTION
[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.
[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0029] The present invention provides a quasi-double-ring frequency selective surface, which is a periodic structure composed of M×N identical units, with no spacing between adjacent units, and M and N are both integers greater than or equal to 2.
[0030] Figure 1 This is a schematic diagram of the structure of a single unit of a double-ring frequency selective surface according to an embodiment of the present invention. As shown in the figure, a single unit is composed of a resonant layer 1 and a substrate 2. The unit is a square structure with a side length of P.
[0031] Figure 2 This is a side view of a single unit of the double-ring frequency selective surface according to an embodiment of the present invention. As shown in the figure, the thickness of the resonant layer 1 is a, and the thickness of the substrate 2 is b.
[0032] Figure 3 This is a schematic diagram of the structure of the resonant layer 1 of a single unit of a double-ring frequency selective surface according to an embodiment of the present invention. Figure 3As shown, the resonant layer 1 includes an external structure 3 and an internal structure 4. The external structure 3 is formed by openings on four sides of a square ring with a side length of d1 and a width of w1, and the opening width is l1. The internal structure 4 is formed by openings on four sides of a square ring with a side length of d2 and a width of w2, and the opening width is l2. There are two extensions 5 at the opening of each side, and the extensions 5 are rectangular. The extensions reach the edge of the unit, and the width is w3 and the length is (P-d2) / 2. The opening width of the external structure is greater than the sum of the opening width of the internal structure and twice the rectangular width of the extension, that is, l1>l2+2*w3. The centers of the internal structure 4 and the external structure 3 coincide, and the line connecting the center of the substrate 2 is perpendicular to the substrate 2 and the resonant layer 1; the sides of the internal structure 4 and the external structure 3 are parallel to the sides corresponding to the substrate 2.
[0033] The thickness a of the resonant layer 1 in this embodiment is 35um. The thickness b of the substrate 2 in this embodiment is 1mm. The values of other structural parameters in this embodiment are: P is 2cm; d1 is 1.95cm, w1 is 0.05cm, l1 is 0.4cm; d2 is 1.4cm, width w2 is 0.1cm, l2 is 0.05cm; w3 is 0.05cm.
[0034] In this embodiment, the material of the resonant layer 1 is copper, and the material of the substrate 2 is a polytetrafluoroethylene F4BM high-frequency antenna board.
[0035] Figure 4 This is a transmission response diagram of the double-ring frequency selective surface of the embodiment of the present invention when the external structure 3 has different lengths. As shown in the figure, when the side length d1 of the external structure 3 gradually decreases, the resonant frequency of the low-frequency stopband remains unchanged, and the resonant frequency of the high-frequency stopband gradually increases.
[0036] Figure 5 This is a transmission response diagram of the double-ring frequency selective surface of the embodiment of the present invention when the external structure 3 has different widths. As shown in the figure, when the width w1 of the external structure 3 gradually increases, the resonant frequency of the low-frequency stopband remains unchanged, and the resonant frequency of the high-frequency stopband gradually increases.
[0037] Depend on Figure 4 and Figure 5 It can be seen that the external structure controls the resonant frequency of the high-frequency stopband.
[0038] Figure 6 This is a transmission response diagram of the double-ring frequency selective surface of the embodiment of the present invention with internal structures 4 having different opening lengths. As shown in the figure, when the opening width l2 of the internal structure 4 gradually increases, the resonant frequency of the high-frequency stopband remains almost unchanged, and the resonant frequency of the low-frequency stopband gradually increases.
[0039] Figure 7This is a transmission response diagram of the double-ring frequency selective surface of the embodiment of the present invention when there are extensions 5 of different widths. As shown in the figure, when the width w3 of the extension gradually increases, the resonance of the high-frequency stopband remains almost unchanged, and the resonance frequency of the low-frequency stopband gradually increases.
[0040] Depend on Figure 6 and Figure 7 It can be seen that the internal structure controls the resonant frequency of the low-frequency stopband.
[0041] The quasi-double-ring frequency selective surface in this embodiment can control the resonance of the high-frequency stopband by adjusting the structural parameters of the external structure, and control the resonance of the low-frequency stopband by adjusting the structural parameters of the internal structure. That is, the internal structure and the external structure independently control the resonance of the low-frequency stopband and the high-frequency stopband respectively. This is different from the traditional double-ring structure in which "the internal structure and the external structure independently control the resonance of the high-frequency stopband and the low-frequency stopband respectively". The present invention provides a different structure for controlling the resonance frequency of the dual-frequency stopband.
[0042] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of the present invention. At the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.
Claims
1. A type of double-ring frequency selective surface, Features: The frequency selective surface is a periodic structure, including M×N units, adjacent units have no spacing, and M and N are both positive integers greater than or equal to 2; The unit includes a resonant layer and a substrate; Along the wave incident direction, there are the resonant layer and the substrate in order; The resonance layer is composed of an internal structure and an external structure nested together; The internal structure and the external structure are two deformed square rings; The internal structure is open on the four sides of the square ring, and there is an extension portion outside the square at the opening of each side; the external structure is open on the four sides of the square ring; each extension portion of the internal structure is rectangular, and the extension portion reaches the edge of the unit; The opening width of the outer structure is greater than the sum of the opening width of the inner structure and twice the rectangular width of the extension portion; The centers of the internal structure and the external structure coincide with each other, and a line connecting the center of the substrate is perpendicular to the substrate and the resonance layer; and the sides of the internal structure and the external structure are parallel to the sides corresponding to the substrate.
2. The quasi-double-ring frequency selective surface according to claim 1, It is characterized in that The material of the resonance layer is any one of copper, gold and silver.
3. The quasi-double-ring frequency selective surface according to claim 1, It is characterized in that The thickness of the resonance layer is in the range of 30-40 um.
4. The quasi-double-ring frequency selective surface according to claim 1, It is characterized in that The material of the substrate is any one of polytetrafluoroethylene F4BM high-frequency antenna board, glass fiber epoxy resin material FR4, polyethylene terephthalate (PET), etc.
5. The quasi-double-ring frequency selective surface according to claim 1, It is characterized in that The thickness of the substrate is in the range of 1-2 mm.