Frequency selective reflector and reflecting structure

Patent metadata

Field	Value
Publication number	US-2024145929-A1
Application number	US-202218548355-A
Country	US
Kind code	A1
Filing date	Mar 4, 2022
Priority date	Mar 4, 2021
Publication date	May 2, 2024
Grant date	—

Abstract

A frequency selective reflector including a reflecting member reflecting the electromagnetic waves; and a dielectric layer that: is disposed at an incident side of the electromagnetic waves with respect to the reflecting member; includes a concave and convex structure in which a plurality of a unit structure including a thickness distribution of increasing thickness in a predetermined direction is arranged; and transmits the electromagnetic waves, wherein the unit structure of the dielectric layer includes a plurality of cell regions of which thickness differs from one another; the dielectric layer includes, as the unit structure, at least a first unit structure including three or more of the cell regions of which thickness differs from one another; and a reflection direction of the electromagnetic waves is controlled by controlling a relative reflection phase distribution of the electromagnetic waves by the thickness distribution of the dielectric layer.

First claim

1 - 19 . (canceled)

20 . A reflecting structure comprising:
a frequency selective reflector reflecting electromagnetic waves in a particular frequency band to a direction different from a regular reflection direction; and a protective member arranged in an upper side of the frequency selective reflector, wherein a thickness of the protective member is less than ¼ of an effective wavelength of the electromagnetic waves propagating in the protective member.

21 . The reflecting structure according to claim 20 ,
wherein the frequency selective reflector includes, in an order from the protective member side,
a dielectric layer including a concave and convex structure in which a plurality of a unit structure including a thickness distribution of increasing thickness in a predetermined direction is arranged, and transmitting the electromagnetic waves; and
a reflecting member reflecting the electromagnetic waves,
wherein the unit structure of the dielectric layer includes a plurality of cell regions of which thickness differs from one another;
in each of the unit structure of the dielectric layer, in a graph setting a horizontal axis as a length of the predetermined direction of the unit structure, and setting a vertical axis as a relative reflection phase when the electromagnetic waves are transmitted through the dielectric layer, reflected by the reflecting member and emitted to the protective member side by being transmitted through the dielectric layer again, in the graph, a value of the relative reflection phase of the electromagnetic waves is over −360° and 0° or less, when a point corresponding to a central position of the predetermined direction in each cell region and corresponding to the relative reflection phase of the electromagnetic waves in each cell region are plotted, and a straight line passing through a point corresponding to a minimum thickness cell region having a minimum thickness is drawn, each point is on a same straight line;
the dielectric layer includes, as the unit structure, at least a first unit structure including three or more of the cell region of which thickness differs from one another; and a reflection direction of the electromagnetic waves is controlled by controlling the relative reflection phase distribution of the electromagnetic waves by the thickness distribution of the dielectric layer.

22 . The reflecting structure according to claim 20 ,
wherein the frequency selective reflector includes, in an order from the protective member side,
a dielectric layer including a concave and convex structure in which a plurality of a unit structure including a thickness distribution of increasing thickness in a predetermined direction is arranged, and transmitting the electromagnetic waves; and
a reflecting member reflecting the electromagnetic waves,
wherein the unit structure of the dielectric layer includes a plurality of cell regions of which thickness differs from one another; in each of the unit structure of the dielectric layer, in a graph setting: a horizontal axis as a relative position when a central position in the predetermined direction of a minimum thickness cell region having a minimum thickness is defined as 0, and a central position of the predetermined direction of a maximum thickness cell region having a maximum thickness is defined as 1; and a vertical axis as a thickness ratio of each cell region with respect to a thickness of the maximum thickness cell region when a thickness of the minimum thickness cell region is defined as 0, and a thickness of the maximum thickness cell region is defined as 1; when a point corresponding to a central position of the predetermined direction of each cell region and corresponding to a thickness ratio of each cell region with respect to a thickness of the maximum thickness cell region is plotted to obtain a regression line of a below formula (1):
y=ax   (1),

a slope “a” of the regression line is 0.7 or more and 1.2 or less, a coefficient of determination of the regression line is 0.9 or more; and the dielectric layer includes, as the unit structure, at least a first unit structure including three or more of the cell regions of which thickness differs from one another.

23 . The reflecting structure according to claim 20 ,
wherein the frequency selective reflector includes, in an order from the protective member side,
a dielectric layer including a concave and convex structure in which a plurality of a unit structure including a thickness distribution of increasing thickness in a predetermined direction is arranged, and transmitting the electromagnetic waves; and
a reflecting member reflecting the electromagnetic waves,

wherein the unit structure of the dielectric layer includes a plurality of cell regions of which thickness differs from one another; in each of the unit structure of the dielectric layer, a difference between a minimum thickness and a maximum thickness is 0.2 mm or more and 15 mm or less; and the dielectric layer includes, as the unit structure, at least a first unit structure including three or more of the cell regions of which thickness differs from one another.

24 . The reflecting structure according to claim 23 , wherein the reflecting member is a frequency selective plate reflecting only the electromagnetic waves.

25 . The reflecting structure according to claim 24 , wherein the reflecting member includes a reflection phase control function controlling a reflection phase of the electromagnetic waves.

26 . The reflecting structure according to claim 20 , wherein the frequency selective reflector includes a reflecting member reflecting the electromagnetic waves; and
the reflecting member includes a reflection phase control function controlling a reflection phase of the electromagnetic waves.

27 . The reflecting structure according to claim 20 , wherein the protective member is supported by the frequency selective reflector.

28 . The reflecting structure according to claim 20 , wherein a supporting member is arranged in an outer periphery of the frequency selective reflector, and the protective member is supported by the supporting member.

29 . The reflecting structure according to claim 20 , wherein the protective member includes, in an order from the frequency selective reflector, an adhesive layer and a protective sheet.

30 . The reflecting structure according to claim 21 , wherein the reflecting member is a frequency selective plate reflecting only the electromagnetic waves.

31 . The reflecting structure according to claim 30 , wherein the reflecting member includes a reflection phase control function controlling a reflection phase of the electromagnetic waves.

32 . The reflecting structure according to claim 22 , wherein the reflecting member is a frequency selective plate reflecting only the electromagnetic waves.

33 . The reflecting structure according to claim 32 , wherein the reflecting member includes a reflection phase control function controlling a reflection phase of the electromagnetic waves.

Assignees

• Dainippon Printing Co Ltd

Inventors

• Miyazaki Yuichi
• Asakura Hiroyuki
• Nakamura Atsuo
• Sekiguchi Takeshi
• Kawano Shigeki

Classifications

• H01Q3/46

  Active lenses or reflecting arrays · CPC title

• H01Q15/0013 Primary

  said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective · CPC title

• H01Q15/14

  Reflecting surfaces; Equivalent structures {(electromagnetic shields H01Q1/526)} · CPC title

• H01Q15/0026 Primary

  said selective devices having a stacked geometry or having multiple layers · CPC title