CN210926346U - A four-petal flower-shaped electromagnetic wave polarization regulator based on metasurface - Google Patents

Abstract

The utility model relates to a four-petal flower-shaped electromagnetic wave polarization regulator based on a metasurface, which is formed by periodically arranging a plurality of polarization units on the same plane. Each polarization unit has three layers, which are a surface metal resonant structure (1), an intermediate dielectric layer (2) and a bottom metal reflection film (3). The utility model adopts a four-petaled flower-shaped metasurface, which realizes the efficient conversion of a vertical incident ray polarized wave into a linearly polarized reflected wave with a polarization plane perpendicular to the incident wave polarization plane in a wide frequency range. In addition, changing the relevant structural parameters of the electromagnetic wave polarization regulator can realize the shift of its working frequency band. The four-petaled flower-shaped electromagnetic wave polarization regulator of the utility model has the advantages of small structure size and high conversion rate, and can be widely used in the fields of communication, sensing, radar and the like.

Description

A four-petal flower-shaped electromagnetic wave polarization regulator based on metasurface

technical field

The invention belongs to the field of electromagnetic wave polarization regulation, and in particular relates to a four-petal flower-shaped electromagnetic wave polarization controller based on a metasurface.

Background technique

Polarization is one of the most important characteristics of electromagnetic waves. According to their different polarization states, electromagnetic waves can be divided into linearly polarized waves, elliptically polarized waves, and circularly polarized waves. The polarization state of electromagnetic waves reflects the propagation process of electromagnetic waves. The asymmetry of the vibration direction of the electric field relative to its propagation direction; since many strange phenomena of electromagnetic waves are related to the polarization state of electromagnetic waves, controlling the polarization state of electromagnetic waves is an important direction in scientific research.

As an artificially assembled material, metamaterials have many novel properties that natural materials do not possess. Two-dimensional metamaterials, also known as metasurfaces, not only retain the exotic properties of three-dimensional metamaterials, but also overcome the difficulties faced in the preparation of three-dimensional metamaterials. Metasurfaces have shown extraordinary properties in manipulating the propagation of electromagnetic waves, especially in the microwave and optical frequency bands, and great progress has been made in the research on polarization manipulation based on anisotropic or chiral metasurfaces. Compared with traditional polarization regulators, metasurface-based polarization regulators have the characteristics of simple structure, flexible design, small size, and light weight, and they can utilize the now very mature standard printed circuit board process or photolithography Therefore, the researchers designed and fabricated a variety of different metasurface electromagnetic wave polarization regulators.

At present, many existing reflective metasurface electromagnetic wave polarization controllers can only achieve efficient polarization regulation for linearly polarized electromagnetic waves in a fixed frequency band, while the regulation ability for linearly polarized electromagnetic waves in other frequency bands is poor, and cannot achieve ultra-high-efficiency polarization regulation. Structural Tunability of Surface Electromagnetic Wave Polarization Regulators.

SUMMARY OF THE INVENTION

The present invention provides a four-petaled flower-shaped electromagnetic wave polarization regulator based on a metasurface, which can realize broadband electromagnetic wave polarization regulation and has structural adjustability.

The technical solution adopted by the present invention to solve the technical problem is as follows: a four-petal flower-shaped electromagnetic wave polarization regulator based on a metasurface, comprising a plurality of polarization units arranged periodically in the same plane.

Each polarization unit includes a three-layer structure, which are a metal resonant structure on the surface layer, an intermediate dielectric layer and a metal reflective film on the bottom layer. The centers of the surface metal resonant structure, the intermediate dielectric layer and the bottom metal reflective film are located on the same vertical line.

The surface metal resonant structure is composed of four metal concentric rings spliced into a four-petal flower-shaped structure, the centers of the four metal concentric rings are on the two mutually perpendicular symmetry axes of the four-petal flower-shaped structure, and the surface The center of the flower-shaped structure is the intersection of the two axes of symmetry; a rectangular void is dug out of the overlapping part of the four metal concentric rings, and the center of the rectangular void coincides with the center of the four-petal flower-shaped structure. When the four metal concentric rings of the four-petal flower-shaped structure are large enough, so that there is no gap around the center O of the structure after the intersection, a rectangular gap can be directly dug out from the overlapping part of the four concentric metal rings; When there is a gap around the center O of the structure after the four metal concentric rings of the four-petal flower-shaped structure intersect, first fill the gap with the same metal material as the surface resonant structure, and then dig out the overlapping part of the four metal concentric rings. Go for a rectangular gap; the rectangular gap can be placed horizontally or at an angle.

The geometry of the underlying metal reflective film is identical to the dielectric layer except for the thickness.

Further, the position of the working frequency band can be effectively changed by adjusting the structural parameters of the surface metal resonant structure.

Further, both the surface metal resonant structure and the bottom metal reflective film are composed of copper foil.

Further, the dielectric layer adopts microwave dielectric materials, and the dielectric materials include FR-4 glass cloth substrates and Taconic series dielectric materials; preferably Taconic series dielectric materials, the dielectric constant of which is between 2 and 3, and the loss The tangent value is between 0.0009 and 0.005.

Further, when the polarization unit is periodically extended, the number of units repeated in the horizontal and vertical directions is the same, that is, the formed periodic array structure is a square array.

The cross-polar reflectivity of the electromagnetic wave polarization controller is defined as R _yx (ω)=|S _1y,1x (ω)| ² , and the co-polar reflectivity is defined as R _xx (ω)=|S _1x,1x (ω)| ² , where S _1y,1x (ω) and S _1x,1x (ω) are S-parameters.

The beneficial effects of the present invention are as follows: 1. The present invention can convert the vertically incident ray polarized wave into the linearly polarized reflected wave perpendicular to the polarization plane of the incident wave with a higher conversion rate in a wider frequency range, and the present invention also The structural tunability of the metasurface electromagnetic wave polarization regulator is realized.

2. When the structural parameters of the present invention are properly selected, the co-polar reflectivity R _xx of the present invention between 14.45 GHz and 17.46 GHz is less than 10%, the cross-polar reflectivity R _yx is greater than 90%, and its polarization The tuning frequency band can be moved with the size change of the surface metal resonant structure. The working frequency band of the present invention can be adjusted by changing the structural parameters of the electromagnetic wave polarization regulator, and can be flexibly changed according to actual requirements in engineering applications.

3. The present invention has a light and thin volume, is easy to process and manufacture, and can be realized by using the now very mature standard printed circuit board technology and photolithography technology.

Description of drawings

FIG. 1 is a partial top view of the present invention.

FIG. 2 is a side view of the polarizing unit structure of the present invention.

FIG. 3 is a top view of the polarization unit structure of the present invention.

FIG. 4 is a graph of cross-polarized reflectivity and co-polarized reflectivity of Embodiment 1 of the present invention.

FIG. 5 is a top view of the structure of the polarization unit according to Embodiment 2 of the present invention.

FIG. 6 is a graph of cross-polarized reflectivity and co-polarized reflectivity of Embodiment 2 of the present invention.

FIG. 7 is a top view of the structure of the polarization unit according to Embodiment 3 of the present invention.

FIG. 8 is a graph of cross-polarized reflectivity and co-polarized reflectivity of Embodiment 3 of the present invention.

The reference numerals are: 1—surface metal resonant structure; 2—intermediate dielectric layer; 3—bottom metal reflective film.

Detailed ways

The present invention utilizes the four-petal flower-shaped metasurface to realize high-efficiency electromagnetic wave polarization conversion in a wide frequency range, and at the same time, the size of the structure can be changed to realize the shift of its working frequency band. The four-petal flower-shaped electromagnetic wave polarization described in the present invention Controllers are used in communications, sensing, and radar, among others.

Below in conjunction with embodiment and accompanying drawing, the present invention is further described:

The invention provides a metasurface-based four-petal flower-shaped electromagnetic wave polarization regulator, which is composed of a plurality of polarization units in the same plane arranged periodically. Pay attention to the repetition of the periodic extension of the polarization units in the horizontal and vertical directions. same number.

Referring to Figure 2, each polarization unit has three layers, which are the surface metal resonant structure, the intermediate dielectric layer and the bottom metal reflective film. The cross section of the polarization unit is a square, the horizontal length is the same as the vertical length, and the side length P is defined as the period length.

The surface metal resonance structure (1) is made of copper foil, and its thickness is 0.017-0.035mm.

As shown in Figure 3, the surface metal resonant structure is composed of four metal concentric rings spliced into a four-petal flower-shaped structure, and the centers of the four metal concentric rings are at the two symmetrical axes that are perpendicular to each other and bisect the four-petal flower-shaped structure. , the center O of the surface metal resonant structure is the midpoint of the symmetry axis; if the concentric rings are large enough so that there is no gap around the center of the structure after the intersection, you can directly dig an arbitrary angle in the overlapping part of the four concentric rings If the concentric rings are relatively small, so that there is a gap around the center of the structure after the intersection, you can first fill the gap with the same material as the surface resonant structure, and then dig out an arbitrary Angled rectangular structure, the rectangle can be placed obliquely; the outer radius dimension R2 of the _four metal concentric rings is _1-1.7mm , and the inner radius dimension R1 is 0.5-1mm. If the center O of the surface metal resonant structure is taken as the coordinate origin, the center coordinates of the four metal concentric rings are O ₁ (-1mm, 1mm), O ₂ (1.5mm, 1.5mm), O ₃ (1mm, - 1mm), O ₄ (-1.5mm, -1.5mm), the distances between the center of the four metal concentric rings and the center of the rectangle O are ｜OO ₁ ｜, ｜OO ₂ ｜, ｜OO ₃ ｜, ｜OO ₄ ｜ , the size of these four distances is 1.4~2.1mm; the size of the dug rectangle also changes with the change of the size of the metal concentric ring, the length L of the rectangle varies from 0.8 to 2mm, and the width W varies from 0.8 ~1mm.

In the present invention, the working frequency band of the linear polarization regulator can be efficiently changed by changing the geometrical parameters of the metal concentric rings and rectangles.

The intermediate dielectric layer (2) is made of microwave dielectric material, such as one of FR-4 glass cloth substrate material and Taconic series substrate material, and its thickness is 1 mm; preferably Taconic series dielectric material, whose dielectric constant Between 2 and 3, the loss tangent value is between 0.0009 and 0.005, and the side length of the intermediate dielectric layer (2) is the same as the period P of the polarization unit.

The bottom metal reflective film (3) is made of one of metals with high reflectivity and not easy to be oxidized, and its thickness is 0.017-0.035mm.

Example 1

The thickness of the metal reflective film set in this embodiment is 0.035mm, and the material is copper foil; the thickness of the dielectric layer is 1mm, the material is TLY-5 (lossy) in the Taconic series, the dielectric constant is 2.2, and the loss tangent is 0.0009; the thickness of the surface metal resonant structure is 0.035mm, and the material is still copper foil; the period of the polarization unit is P=8mm, W=L=0.5mm, R ₂ =1.5mm, R ₁ =0.7mm, |OO ₁ | = |OO ₃ |=2.1 mm, |OO ₂ |= |OO4|=1.4 mm. At this time, the angle between the long side of the rectangle and the y-axis is 0 degrees. The co-polarized reflectivity Rxx and the cross-polarized reflectivity Ryx of this embodiment, as shown in FIG. 4 , the cross-polarized reflectivity of the electromagnetic wave polarization regulator between 14.45 GHz and 17.46 GHz is greater than 90%, and the maximum value is is 98.4%.

Example 2

The thickness of the metal reflective film set in this embodiment is 0.035mm, and the material is copper foil; the thickness of the dielectric layer is 1mm, the material is TLY-9 (lossy) in the Taconic series, the dielectric constant is 2.5, and the loss tangent value is 0.0019; the thickness of the surface metal resonant structure is 0.035mm, and the material is still copper foil. Period P=8mm, L=1.2mm, W=0.8mm, R2=1.5mm, R1 ₌ 1mm, | _OO1 |=| _OO3 |=2.1mm, | _OO2 | ₌ | _OO4 |=1.4mm. At this time, the angle between the long side of the rectangle and the y-axis is 0 degrees, as shown in FIG. 5 . The co-polar reflectivity Rxx and the cross-polar reflectivity Ryx of this embodiment are shown in Figure 6; the frequency range where Ryx is greater than 90% is 13.28-16.02 GHz, and the maximum value is 96.8%; It was found that the working frequency band of Example 2 was changed from 14.45GHz-17.46GHz to 13.28-16.02GHz, which was shifted compared with Example 1, and the structural adjustability of the metasurface electromagnetic wave polarization regulator was realized.

Example 3

The thickness of the metal reflective film set in this embodiment is 0.035mm, and the material is copper foil; the thickness of the dielectric layer is 1mm, the material is TLY-9 (lossy) in the Taconic series, the dielectric constant is 2.5, and the loss tangent value is 0.0019; the thickness of the surface metal resonant structure is 0.035mm, and the material is still copper foil. Period P=8mm, L=0.6mm, W=0.4mm, R2=1.5mm, R1 ₌ 1mm, | _OO1 |=| _OO3 |=2.1mm, | _OO2 | ₌ | _OO4 |=1.4mm. At this time, the angle between the long side of the rectangle and the y-axis is 40 degrees, as shown in FIG. 7 . The co-polar reflectivity Rxx and the cross-polar reflectivity Ryx of this embodiment are shown in Figure 8; the frequency range where Ryx is greater than 90% is 13.28-16.02 GHz, and the maximum value is 96.8%; It is found that the rectangular gap can be placed horizontally or obliquely, and the electromagnetic wave polarization regulator will maintain high performance.

The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims of the present invention and equivalent technical scope, then the present invention will also Intended to contain these alterations and variants.

Claims (8)

1. A quadralobe flower type electromagnetic wave polarization controller based on a super surface comprises a plurality of polarization units which are periodically arranged in the same plane; the method is characterized in that:

each polarization unit structure comprises three layers, namely a surface metal resonance structure (1), a middle dielectric layer (2) and a bottom metal reflection film (3); the surface layer metal resonance structure (1) is a four-petal flower type structure formed by splicing four metal concentric rings, the circle centers of the four metal concentric rings are positioned on two mutually vertical symmetry axes of the four-petal flower type structure, and the center of the surface layer four-petal flower type structure is the intersection point of the two mutually vertical symmetry axes; digging a rectangular gap at the overlapped part of the four metal concentric rings, wherein the center of the rectangular gap is superposed with the center of the four-petal flower type structure; the centers of the surface metal resonance structure, the middle dielectric layer and the bottom metal reflection film are positioned on the same vertical line.

2. The electromagnetic wave polarization regulator based on the quadrilaterals flower type of the super surface of claim 1, characterized in that: when the four metal concentric rings of the four-petal flower type structure are large enough, so that no gap exists around the center O of the structure after intersection, a rectangular gap can be directly dug in the overlapped part of the four concentric rings; when a gap is formed around the center O of the structure after the four concentric rings of the four-petal flower type structure are intersected, firstly filling the gap with a metal material which is the same as the surface layer resonance structure, and then excavating a rectangular gap at the overlapped part of the four concentric rings; the rectangular gap is horizontally arranged or obliquely arranged.

3. The electromagnetic wave polarization regulator based on the quadrilaterals flower type of the super surface of claim 1, characterized in that: the inner radius R of the metal concentric ring₁The size is between 0.5 and 1mm, and the outer radius R₂The size is 1-1.7 mm; the width of the rectangular gap is 0.8-1 mm, and the length of the rectangular gap is 0.8-2 mm; the working frequency band of the polarization regulator can be adjusted by adjusting the inner radius of the metal concentric circular ring and the size of the rectangle.

4. The electromagnetic wave polarization regulator based on the quadrilaterals flower type of the super surface of claim 1, characterized in that: the distance between the centers of the four concentric metal rings and the center O of the surface layer metal resonance structure is 1.4-2.1 mm.

5. The electromagnetic wave polarization regulator based on the quadrilaterals flower type of the super surface of claim 1, characterized in that: the intermediate dielectric layer may use an FR-4 glass cloth substrate and a Taconic series dielectric material.

6. The electromagnetic wave polarization regulator based on the quadrilaterals flower type of the super surface of claim 1, characterized in that: the surface metal resonance structure and the bottom metal reflection film can be made of gold, silver, copper, aluminum and other metals.

7. The electromagnetic wave polarization regulator of the super-surface-based quadralobe type as claimed in claim 1 and claim 2, wherein: the period P of the polarization unit is 7-9 mm; the thickness of the dielectric layer is 0.9-1.1 mm, and the thickness of the bottom metal reflecting film and the thickness of the surface metal resonance structure are 0.017-0.035 mm.

8. The electromagnetic wave polarization regulator of the super-surface-based quadralobe type as claimed in claim 1 and claim 2, wherein: and when viewed from the direction vertical to the plane of the dielectric layer, the number of the polarization units in the transverse direction and the longitudinal direction is equal, namely the formed periodic array is a square array.

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