阅读说明：本技术 一种宽带复合耦合型频率选择表面结构及其单元结构 (Broadband composite coupling type frequency selection surface structure and unit structure thereof ) 是由 焦健 曾雪锋 于 2020-05-07 设计创作，主要内容包括：本发明涉及一种新型宽带复合耦合型频率选择表面结构及其单元结构,属于电磁场与微波技术领域。本发明提出的频率选择表面自上而下依次包括：第一频率选择表面层、介质层和第二频率选择表面层,其中,第一频率选择表面层由周期排列的复合周期单元结构组成,第二频率选择表面层由金属屏上周期排列的Y形孔径单元组成,介质层的介电常数为2.0~5.0,厚度为0.1mm-0.5mm。本发明具有周期单元结构简单、剖面低、易于随形贴敷、超宽的阻带带宽、阻带顶部平坦、阻带边缘陡直性好的优势,同时具有良好的入射角度稳定性。(The invention relates to a novel broadband composite coupling type frequency selective surface structure and a unit structure thereof, belonging to the technical field of electromagnetic fields and microwaves. The frequency selective surface provided by the invention comprises the following components in sequence from top to bottom: the metal screen comprises a first frequency selective surface layer, a dielectric layer and a second frequency selective surface layer, wherein the first frequency selective surface layer is composed of composite periodic unit structures which are periodically arranged, the second frequency selective surface layer is composed of Y-shaped aperture units which are periodically arranged on the metal screen, the dielectric constant of the dielectric layer is 2.0-5.0, and the thickness of the dielectric layer is 0.1mm-0.5 mm. The invention has the advantages of simple periodic unit structure, low section, easy shape-following application, ultra-wide stop band bandwidth, flat top of the stop band, and good steepness of the stop band edge, and has good stability of the incident angle.)

1. A broadband composite coupling type frequency selective surface structure is characterized by sequentially comprising from top to bottom: the frequency selective surface layer comprises a first frequency selective surface layer (1), a dielectric layer (2) and a second frequency selective surface layer (3), wherein the first frequency selective surface layer (1) is composed of composite periodic unit structures (4) which are periodically arranged, and the second frequency selective surface layer (3) is composed of Y-shaped aperture units (8) which are periodically arranged on a metal screen (7).

2. The broadband composite-coupled frequency selective surface structure according to claim 1, wherein the dielectric layer (2) has a dielectric constant of 2.0 to 5.0 and a thickness of 0.1mm to 0.5 mm.

3. A broadband complex-coupling type frequency selective surface structure according to claim 1, wherein the complex periodic unit structure (4) is composed of a first Y-shaped metal patch unit (5) and a second Y-shaped metal patch unit (6).

4. A broadband complex coupling type frequency selective surface structure according to claim 3, wherein the first Y-shaped metal patch element (5) and the second Y-shaped metal patch element (6) each have three arms, and each arm has the same arm length and the same arm width, and two adjacent arms form an included angle of 120 °.

5. A broadband complex coupling type frequency selective surface structure according to any one of claims 1 and 3, characterized in that the Y-shaped aperture element (8) is a complementary structure of the first Y-shaped metal patch element (5).

6. A broadband complex coupling type frequency selective surface structure according to any one of claims 1, 3 and 5, characterized in that the centers of the first Y-shaped metal patch element (5) and the second Y-shaped metal patch element (6) are coincident with the center of the Y-shaped aperture element (8).

7. A broadband complex coupling type frequency selective surface structure according to any one of claims 1 and 3, characterized in that the first Y-shaped metal patch element (5), the second Y-shaped metal patch element (6) and the metal screen (7) are made of copper foil.

Technical Field

The invention belongs to the technical field of electromagnetic fields and microwaves, and particularly relates to a broadband composite coupling type frequency selective surface structure and a unit structure thereof.

Background

The Frequency Selective Surface (FSS) is an artificial electromagnetic material capable of regulating and controlling electromagnetic waves, has a unique filtering function, and is widely applied to the fields of radar stealth, aerospace, satellite communication and the like. The frequency selective surface is also a main technology for improving the stealth performance of novel weaponry and the stealth performance of the conventional weaponry, and is widely applied to the wave bands of visible light, infrared light, millimeter waves, microwaves and the like.

With the development and application of broadband and ultra-wideband radar, the requirement of broadband communication increases, and the requirement of the broadband characteristic of the FSS is more and more urgent. In the past research, in order to obtain the broadband characteristic of the FSS, a curling and interdigital technology or a multilayer FSS array cascading technology is generally adopted, but both the technologies cause the increase of design variables, not only cause difficulty in design, but also easily cause the high profile of the broadband FSS, and cause the FSS to have the bottleneck that the FSS cannot follow the shape and is difficult to attach in practical application. Meanwhile, under the conditions of limited application space and large curvature, the difficulty in obtaining stable electromagnetic transmission characteristics is always a technical problem of FSS in practical application. Therefore, how to realize stable transmission and wide operating bandwidth by using a low-profile structure is a technical bottleneck to be broken through.

Disclosure of Invention

The invention provides a broadband composite coupling type frequency selection surface structure and a unit structure thereof, and aims to solve the technical problem that stable broadband transmission is difficult to realize by using a low-profile FSS in the prior art.

The invention provides a broadband composite coupling type frequency selective surface structure and a unit structure thereof, which sequentially comprise from top to bottom: a first frequency-selective surface layer (1), a dielectric layer (2) and a second frequency-selective surface layer (3).

The first frequency selective surface layer (1) is composed of a composite periodic unit structure (4) arranged periodically.

The second frequency selective surface layer (3) is composed of Y-shaped aperture units (8) which are periodically arranged on a metal screen (7).

The dielectric constant of the dielectric layer (2) is 2.0-5.0, and the thickness is 0.1mm-0.5 mm.

The composite periodic unit structure (4) is composed of a first Y-shaped metal patch unit (5) and a second Y-shaped metal patch unit (6).

The first Y-shaped metal patch unit (5) and the second Y-shaped metal patch unit (6) are provided with three arms, the arm lengths of the arms are equal, the arm widths of the arms are equal, and an included angle of 120 degrees is formed between every two adjacent arms.

The Y-shaped aperture unit (8) is a complementary structure of the first Y-shaped metal patch unit (5).

The centers of the first Y-shaped metal patch unit (5) and the second Y-shaped metal patch unit (6) are coincided with the center of the Y-shaped aperture unit (8).

The first Y-shaped metal patch unit (5), the second Y-shaped metal patch unit (6) and the metal screen (7) are made of copper foils.

Compared with the prior art, the method has the following beneficial effects.

(1) The broadband composite coupling type frequency selective surface structure provided by the invention is composed of a Y-shaped patch FSS layer with a composite periodic unit, a dielectric layer and a Y-shaped aperture FSS layer, and is simple in structure and convenient to process and manufacture.

(2) The whole thickness of the broadband composite coupling type frequency selection surface structure provided by the invention is close to the thickness of a dielectric layer, namely 0.1mm-0.5mm, and the broadband composite coupling type frequency selection surface structure has good performance of low section and is easy to be attached along with the shape.

(3) The broadband composite coupling type frequency selective surface structure provided by the invention is suitable for microwave frequency bands, has ultra-wide stop band bandwidth, flat top of the stop band and good steepness of the edge of the stop band.

(4) The broadband composite coupling type frequency selective surface structure provided by the invention has good incident angle stability, and has stable stop band bandwidth and stable transmission characteristic when the incident angle of electromagnetic waves is 60 degrees.

Drawings

FIG. 1 is a cross-sectional view of a frequency selective surface structure according to the present invention;

FIG. 2 is a partial schematic view of a first frequency selective surface layer (1) of the present invention;

FIG. 3 is a schematic diagram of a composite periodic cell structure of the composite periodic cell structure (4) of the present invention;

FIG. 4 is a partial schematic view of a second frequency selective surface layer (3) of the present invention;

FIG. 5 is a schematic diagram of a periodic unit structure of the Y-shaped aperture unit (8) of the present invention;

fig. 6 is a simulation result diagram of a broadband complex coupling type frequency selective surface structure according to an embodiment of the present invention.

Detailed Description

The present invention provides a wideband composite coupling type frequency selective surface structure and a unit structure thereof, which will be described in detail with reference to the accompanying drawings and embodiments, wherein the embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

As shown in fig. 1, the broadband composite coupling type frequency selective surface structure provided in this embodiment sequentially includes, from top to bottom, a first frequency selective surface layer 1, a dielectric layer 2, and a second frequency selective surface layer 3, where the dielectric constant of the dielectric layer 2 is 2.0-5.0, and the thickness d is 0.1mm-0.5 mm.

As shown in fig. 2, the first frequency selective surface layer 1 of the broadband complex coupling type frequency selective surface structure provided in the present embodiment is composed of a complex periodic unit structure 4 arranged periodically.

As shown in FIG. 3, the composite periodic unit structure 4 is composed of a first Y-shaped metal patch unit 5 and a second Y-shaped metal patch unit 6, wherein each of the first Y-shaped metal patch unit 5 and the second Y-shaped metal patch unit 6 has three arms, the arm lengths of the arms are equal, the arm widths of the arms are equal, and an included angle of 120 degrees is formed between two adjacent arms, namely L₁=L₂，w₁=w₂，α=120°。

As shown in fig. 4 and 5, the second frequency selective surface layer 3 of the broadband composite coupling type frequency selective surface structure provided by this embodiment is composed of Y-shaped aperture units 8 periodically arranged on the metal screen 7, and the Y-shaped aperture units 8 are complementary structures of the first Y-shaped metal patch unit 5, so that the Y-shaped aperture units 8 and the first Y-shaped metal patch unit 5 have the same structural parameters, that is, the arm lengths of the arms are equal, the arm widths of the arms are equal, and an included angle of 120 ° is formed between two adjacent arms, that is, L₃=L₁，w₃=w₁，α=120°。

The first Y-shaped metal patch unit 5, the second Y-shaped metal patch unit 6 and the metal screen 7 are made of copper foils.

The characteristic parameter of the broadband composite coupling type frequency selective surface structure and the periodic unit structure thereof provided by the embodiment is Dx₁=8.0mm，Dx₂=4.0mm，Dy₁= Dy₂=4.2mm，L₁=L₂=L₃=2mm，w₁=w₂=w₃=0.5mm, the dielectric constant of the dielectric layer 2 is 3.0, and the thickness d is 0.2 mm.

Fig. 6 is a simulation result of the present embodiment, and fig. 6 (a) and (b) are curves of reflection coefficient and transmission coefficient of the TE polarized wave with the incident angle varying from 0 ° to 60 °, respectively, and it can be seen that a broadband complex coupling type frequency selective surface structure provided by the present embodiment produces a stop band with an extremely flat top and a good edge steepness in the range of 14-19GHz, and the frequency selective surface has good incident angle stability.

The broadband composite coupling type frequency selection surface structure can realize broadband stable transmission with a low-profile structure.