Sheet-type metamaterial and sheet-type lens

Patent metadata

Field	Value
Publication number	US-10903579-B2
Application number	US-201716080611-A
Country	US
Kind code	B2
Filing date	Feb 7, 2017
Priority date	Feb 29, 2016
Publication date	Jan 26, 2021
Grant date	Jan 26, 2021

Abstract

A sheet-type metamaterial includes: a film-shaped dielectric substrate; a first and second wire array formed on the dielectric substrate's front surface and back surface respectively. The first wire array includes elongated metallic first cut wires of a length aligned in a y-axis direction with a gap g therebetween and in an x-axis direction with space s therebetween. The second wire array includes second cut wires having the same shape as first cut wires and aligned so as to overlap first cut wires and to be symmetric with the first cut wires. With a design frequency set at 0.51 THz, the dielectric substrate's thickness d is set at about 50 μm, space s is set at about 361 μm, gap g is set at about 106 μm, and the length of first and second cut wires is set at a length approximate to a value to generate resonance at a working frequency.

First claim

The invention claimed is:

1. A sheet-type metamaterial comprising:
a film-shaped dielectric substrate;
a first wire array formed on one surface of the dielectric substrate; and
a second wire array formed on an opposite surface of the dielectric substrate, wherein
the first wire array includes elongated metallic first cut wires of a predetermined length l aligned in a direction of a y axis of the dielectric substrate with a gap g therebetween and in an x-axis direction perpendicular to the y axis with space s therebetween,
the second wire array includes metallic second cut wires having the same shape as the first cut wires and aligned so as to overlap the first cut wires and to be symmetric with the first cut wires, and
with a design frequency set at 0.51 THz, a thickness d of the dielectric substrate is set at 50 μm, the space s is set at 360.7 μm, the gap g is set at 105 μm or 106 μm, the width w of the first cut wires and the second cut wires is set at 120.2 μm and the length l of the first cut wires and the second cut wires is set at 202.2 μm or 205 μm.

2. A sheet-type lens comprising a large number of unit cells aligned on a film-shaped dielectric substrate, wherein
the unit cells each include an elongated metallic first cut wire of a predetermined length l formed on one surface of the dielectric substrate, and a metallic second cut wire having the same shape as the first cut wire and formed on an opposite surface of the dielectric substrate,
the first cut wires of the unit cells are aligned on the one surface of the dielectric substrate in a y-axis direction with a gap g therebetween and in an x-axis direction perpendicular to the y-axis direction with space s therebetween,
the second cut wires of the unit cells are aligned on the opposite surface of the dielectric substrate in the y-axis direction with the gap g therebetween and in the x-axis direction perpendicular to the y-axis direction with the space s therebetween,
the first cut wire and the second cut wire each have a long axis extending substantially parallel to the y-axis direction,
the dielectric substrate has a region divided into n regions from a region at a central part to a region at an outer edge of the dielectric substrate,
an innermost first region R1 has a positive refractive index,
an outermost n-th region Rn has a negative refractive index,
a predetermined region Rk between the first region R1 and the n-th region Rn has a zero refractive index, and
a refractive index is reduced gradually with an increasing distance from the first region R1 toward the n-th region Rn,
wherein
in regions between the first region R1 and the region Rk, the first cut wire and the second cut wire are arranged to overlap each other and to be symmetric with each other, and
in regions between a region R(k+1) next to the region Rk and the n-th region Rn, the first cut wire and the second cut wire are arranged to overlap each other and to be asymmetric with each other by being shifted in the y-axis direction.

3. The sheet-type lens according to claim 2 , wherein
to obtain a predetermined refractive index, dimensions about the first cut wire and the second cut wire including a width w, the predetermined length l, the space s, and the gap g are adjusted in regions from the first region to the n-th region.

Assignees

• National Univ Corporation Tokyo Univ Of Agriculture And Technology

Inventors

• Suzuki Takehito

Classifications

• H01Q15/04

  comprising wave-guiding channel or channels bounded by effective conductive surfaces substantially perpendicular to the electric vector of the wave, e.g. parallel-plate waveguide lens · CPC title

• H01Q15/0086 Primary

  said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials · CPC title

• H01Q15/10

  comprising three-dimensional [3D] array of impedance discontinuities, e.g. holes in conductive surfaces or conductive discs forming artificial dielectric · CPC title

• G02B1/007

  made of negative effective refractive index materials · CPC title