CN108336501B

CN108336501B - Reflected terahertz wave direction controller

Info

Publication number: CN108336501B
Application number: CN201810065300.6A
Authority: CN
Inventors: 李九生
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2018-01-23
Filing date: 2018-01-23
Publication date: 2020-10-30
Anticipated expiration: 2038-01-23
Also published as: CN108336501A

Abstract

The invention discloses a direction controller for reflecting terahertz waves. The super-cell array is formed by arranging four super-cells in a certain sequence, wherein each super-cell is composed of 4 multiplied by 4 identical cell structures, and the four cell structures are total, wherein basic structure cells with adjacent sizes have the same reflection phase at the working initial frequency, but have different phase sensitivities in the whole working frequency band, and when the frequency is increased to the working cutoff frequency, the phase difference of the adjacent cell structures reaches the maximum and is 90 degrees; the terahertz wave reflecting direction controller has the characteristic that the phase difference of adjacent unit structures is increased along with the increase of the frequency, so that the terahertz wave can be reflected to different directions only by changing the working frequency. The invention has the advantages of simple structure, easy processing, good control effect and the like. The terahertz frequency-sweeping device has great potential application value in the aspects of terahertz communication, terahertz frequency-sweeping devices and the like.

Description

Reflected terahertz wave direction controller

Technical Field

The invention relates to the field of terahertz wave control, in particular to a direction controller for reflecting terahertz waves.

Background

Metamaterials are artificial electromagnetic media consisting of periodic or aperiodic subwavelength structures, which have unique properties not possessed by natural media, such as negative refractive index, negative dielectric constant and the like. With its advent, it soon became a focus of research in the scientific community. Many singular phenomena are realized by utilizing metamaterials, including singular reflection, invisible cloak, optical prism and the like. In addition, with the advent of processing technology, related metamaterial-based devices, such as absorbers, filters, switches, modulators, and the like, have also been rapidly developed. But reports on related devices for controlling terahertz wave reflection are few.

With the emergence of the generalized Fresnel law, the research speed of terahertz wave control is accelerated by combining the law with the metamaterial, and the modulation of amplitude, phase and the like of the terahertz wave is realized. However, these devices have a common characteristic that they can only work at a single frequency point or that they have a single fixed function after the super-surface structure is designed, and thus, it is impossible to implement multiple functions using one super-surface structure, for example, it is impossible to implement terahertz wave deflection in multiple directions. Based on the defects, the invention designs the reflection terahertz wave controller which can control the terahertz wave to be reflected to a plurality of directions by using the same super surface.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a super-surface structure which can realize multi-angle reflection of reflected terahertz waves. In order to achieve the purpose, the technical scheme is as follows:

the controller comprises four super units, wherein each super unit consists of 4 multiplied by 4 identical unit structures, the four super units have four unit structures in total, each unit structure comprises a bottom metal sheet, a middle polyimide layer and a top-layer open-ended resonance layer, the top-layer open-ended resonance layer is formed by respectively forming a square notch in the center of four edges of a square metal sheet, and the four square notches are completely identical in shape and size and are centrosymmetric; the four super units are sequentially arranged in 4 rows, only one super unit is arranged in each row, and the number of the super units in each row is the same; the total length of the top layer open resonant layer in the 4 rows of super units is gradually increased, the unit structures of the super units in the adjacent rows have the same reflection phase at the initial working frequency, but have different phase sensitivities in the whole working frequency band, and when the frequency is increased to the working cut-off frequency, the phase difference of the unit structures of the super units in the adjacent rows is 90 degrees. The phase sensitivity of the unit structure can be changed by adjusting the size parameter of the top layer open resonator layer. The terahertz wave reflecting direction controller has the characteristic that the phase difference of adjacent unit structures is increased along with the increase of the frequency, so that the terahertz wave can be reflected to different directions only by changing the working frequency.

Based on the above scheme, the following preferable modes can be further adopted:

the bottom layer metal sheet is a square copper sheet with the side length of 90 mu m and the thickness of 0.2 mu m. The side length of the intermediate polyimide layer is 90 μm and the thickness is 25 μm. The number of the super units in each column is 8. In the four super cells, the total lengths of the top-layer open resonance layers in the cell structure are respectively 30 micrometers, 72 micrometers, 80 micrometers and 83 micrometers, and the side length of the square notch is 3/8 of the side length of the square metal sheet.

The invention has the advantages of simple structure, easy processing, good control effect and the like. The terahertz frequency-sweeping device has great potential application value in the aspects of terahertz communication, terahertz frequency-sweeping devices and the like.

Drawings

FIG. 1 is a top view of a superunit of a group reflected terahertz wave direction controller; wherein: (a) is a top view of the super unit 1, which is formed by arranging 4 multiplied by 4 unit structures 1; (b) is a top view of the super unit 2, which is formed by arranging 4 x 4 unit structures 2; (c) is a top view of the super unit 3, which is formed by arranging 4 multiplied by 4 unit structures; (d) is a top view of the super cell 4, which is formed by arranging 4 × 4 cell structures 4;

FIG. 2 is a three-dimensional schematic of a cell structure;

FIG. 3 is a three-dimensional schematic of 4 cell structures;

FIG. 4 is a simulated phase-frequency diagram of four cell structures when the total length L of the top-layer split-resonance layer is taken as L1, L2, L3 and L4, respectively; wherein: (a) a three-dimensional schematic of unit structure 1, wherein L-L1-30 μm; (b) a three-dimensional schematic of unit structure 2, wherein L-L2-72 μm; (c) a three-dimensional schematic of unit structure 3, wherein L-L3-80 μm; (d) a three-dimensional schematic of unit structure 4, wherein L-L1-83 μm;

FIG. 5 is a graph of simulation results for a reflected terahertz wave direction controller for vertically incident terahertz waves at different frequencies; wherein: (a) is a 3D far field simulation result diagram under 0.4 THz; (b) is a 3D far field simulation result diagram under 0.5 THz; (c) is a 3D far field simulation result diagram under 0.6 THz; (d) is a 3D far field simulation result diagram under 0.75 THz; (e) an xoz surface simulation result chart under 0.4 THz; (f) an xoz face simulation result chart under 0.5 THz; (g) an xoz surface simulation result chart under 0.6 THz; (h) the result is a graph of xoz plane simulation results at 0.75 THz.

Detailed Description

As shown in fig. 1 to 3, a directional controller for reflected terahertz waves includes four types of super cells, wherein each type of super cell is composed of 4 × 4 identical cell structures. The unit structure in each super unit is single, so four super units have four unit structures. Each unit structure has the same basic composition and comprises a bottom metal sheet 1, a middle polyimide layer 2 and a top open-ended resonance layer, wherein the top open-ended resonance layer (the reference numbers are 3, 4, 5 and 6 respectively) is formed by respectively forming a square notch on four sides of a square metal sheet, and the square notch is positioned in the center of each side. The four square notches on each square metal sheet are identical in shape and size and are centrosymmetric. The four types of super units are arranged in a 4 x 8 array, 4 columns are provided, and each column is provided with 8 identical super units. In each row, from left to right, a super cell 1, a super cell 2, a super cell 3 and a super cell 4 are arranged in sequence. All unit structures in adjacent super unit all link up closely, and bottom metal sheet 1, middle polyimide layer 2 are processing of integration. The total length of the top layer open resonator layers of the super unit 1, the super unit 2, the super unit 3 and the super unit 4 is gradually increased, namely, the total length of the top layer open resonator layer 3 of the super unit 1 is minimum, the top layer open resonator layer 4 of the super unit 2 and the top layer open resonator layer 5 of the super unit 3 are gradually increased, and the total length of the top layer open resonator layer 6 of the super unit 4 is maximum. The phase sensitivity of the cell structure can be adjusted by changing the total length of the split resonance layer. In the 4-column super unit, the cell structures of the adjacent column super unit are firstly kept to have the same reflection phase at the initial working frequency, but due to different phase sensitivities in the whole working frequency band, the phase difference of the cell structures of the adjacent column super unit is 90 degrees when the frequency is increased to the working cut-off frequency. The phase sensitivity of the unit structure can be changed by adjusting the size parameters of the top-layer split-resonance layer, so that the size of each split-resonance layer needs to be optimally designed. The working initial frequency and the working cut-off frequency can be determined according to actual needs. The terahertz wave reflecting direction controller has the characteristic that the phase difference of adjacent unit structures is increased along with the increase of the frequency, so that the terahertz wave can be reflected to different directions only by changing the working frequency.

Example 1

In this embodiment, the structure of the terahertz wave reflecting direction controller is as described above (fig. 1 to 3), and is not described again. However, in this embodiment, the specific parameters of each component are as follows: the material of the bottom metal sheet 1 and the top open resonator layer are both 5.95 × 10 in conductivity⁷S/m, 0.2 μm thick copper, 3.0 relative dielectric constant of polyimide, and 25 μm thick. The bottom metal foil 1 and the intermediate polyimide layer 2 are made of the sameThe squares are 90 μm on each side. The four unit structures are obtained by changing the side length L of the square copper block. In four cell structures of super cell 1, super cell 2, super cell 3, and super cell 4, the lengths L of the square copper sheets of top open resonator layer 3, top open resonator layer 4, top open resonator layer 5, and top open resonator layer 6 are respectively taken as L1 ═ 30 μm (super cell 1), L2 ═ 72 μm (super cell 2), L3 ═ 80 μm (super cell 3), and L4 ═ 83 μm (super cell 4), and the side length of the square notch is 3/8, that is, 3L/8, the side length of the square copper sheet. Thus, the four cell structures have the same initial phase at the initial frequency, and the adjacent basic cells are 90 degrees out of phase at the cutoff frequency. The total length of each super cell is 360 μm by 360 μm. Finally, in the top surface resonance layer of the reflective terahertz wave direction controller, the x direction (the row direction of the array) is formed by sequentially arranging one super unit 1, one super unit 2, one super unit 3 and one super unit 4, the y direction (the column direction of the array) is sequentially provided with 8 super units, the 8 super units 1, 8 super units 2, 8 super units 3 and 8 super units 4 are sequentially provided from left to right, and the overall size of the reflective terahertz wave direction controller is 1440 μm × 2880 μm. A simulation result diagram of the reflected terahertz wave direction controller is shown in fig. 4. As can be seen from fig. 4 and 5, as the frequency increases, the reflected terahertz wave is reflected to different directions, and when the frequency increases from 0.4THz to 7.5THz, the main lobe of the reflected terahertz wave correspondingly increases from 0 degree to 15 degrees, thereby realizing the directional control of the reflected terahertz wave.

Claims

1. A reflecting terahertz wave direction controller is characterized by comprising four super units, wherein each super unit is composed of 4 multiplied by 4 identical unit structures, the four super units have four unit structures in total, each unit structure comprises a bottom metal sheet (1), a middle polyimide layer (2) and a top-layer opening resonance layer, the top-layer opening resonance layer is formed by respectively forming a square notch in the centers of four edges of a square metal sheet, and the four square notches are completely identical in shape and size and are centrosymmetric; the four super units are sequentially arranged in 4 rows, only one super unit is arranged in each row, and the number of the super units in each row is the same; the total length of the top layer open resonant layer in the 4 rows of super units is gradually increased, the unit structures of the super units in the adjacent rows have the same reflection phase at the initial working frequency, but have different phase sensitivities in the whole working frequency band, and when the frequency is increased to the working cutoff frequency, the phase difference of the unit structures of the super units in the adjacent rows is 90 degrees;

the bottom layer metal sheet (1) is a square copper sheet with the side length of 90 mu m and the thickness of 0.2 mu m;

the middle polyimide layer (2) is square, the side length is 90 micrometers, the thickness is 25 micrometers, and the relative dielectric constant of polyimide is 3.0;

the number of each row of super units is 8;

in the four super cells, the total lengths of top-layer opening resonance layers in the cell structure are respectively 30 micrometers, 72 micrometers, 80 micrometers and 83 micrometers, and the side length of a square notch is 3/8 of the side length of the square metal sheet;

the materials of the bottom metal sheet (1) and the top open resonator layer are both 5.95 × 10 in conductivity⁷S/m。