JP-7855141-B2 - reflector

Inventors

• 永岡 直樹
• 加藤 大貴

Assignees

• 日東電工株式会社

Dates

Publication Date

20260507

Application Date

20240328

Priority Date

20230331

Claims (9)

1. Dielectric layer and A conductive layer formed on the first surface of the dielectric layer, which includes a plurality of conductor patterns that reflect incident waves, A ground layer formed on the second surface of the dielectric layer opposite to the first surface, It has, The aforementioned conductor patterns are arranged in multiple locations along a predetermined direction, Among the plurality of conductor patterns, the standard deviation σ of the difference between the center-to-center distance between a reference conductor pattern and an arbitrary conductor pattern and the ideal distance along the predetermined direction is 0.5 mm or more and 1.5 mm or less. Reflector.
2. Among the plurality of conductor patterns, when an incident wave with the same phase is incident on a reference conductor pattern and the m-th conductor pattern in the direction of arrangement from the reference conductor pattern, the distance between the centers of the reference conductor pattern and the m-th conductor pattern at which the intensity of the reflected wave is strongest is defined as the ideal distance dm of the m-th conductor pattern. The distance between the centers of the reference conductor pattern and the mth conductor pattern formed on the first surface of the dielectric layer is defined as the actual distance dm' of the mth conductor pattern. Let |dm' - dm| be the absolute value of the difference between the actual distance dm' and the ideal distance dm. Let m be an integer greater than or equal to 1. The standard deviation of the group consisting of |dm'-dm| for each conductor pattern other than the aforementioned reference conductor pattern is 0.5 mm or more and 1.5 mm or less. The reflector according to claim 1.
3. An adhesive layer provided on the side of the ground layer opposite to the dielectric layer, A reflector according to claim 1, having the following features.
4. A protective layer covering the conductive layer, The reflector according to claim 1, further comprising:
5. The protective layer has a thickness of 0.1 mm or more and 1.0 mm or less, and a relative permittivity of 2.0 or less. The reflector according to claim 4.
6. The thickness of the dielectric layer is 0.3 mm or more and 1.0 mm or less. The reflector according to claim 1.
7. The length of the conductor pattern is 2.0 mm or more and 5.0 mm or less. The reflector according to claim 1.
8. The frequency bandwidth of the reflection per unit thickness of the reflector exceeds 6.5 GHz/mm. The reflector according to claim 1.
9. The dielectric layer is formed from a composite of a fluorinated resin and an inorganic porous aggregate, and the porosity of the dielectric layer is 20% or more. A reflector according to any one of claims 1 to 8.

Description

The present invention relates to a reflector, and more particularly to a reflector having a metasurface. Using high-frequency radio waves such as microwaves, millimeter waves, and terahertz waves in wireless communication enables high-speed, high-capacity communication. On the other hand, high-frequency radio waves from 1 GHz to 10 THz have strong directivity, and the presence of obstacles between the transmitting and receiving antennas can prevent the radio waves from reaching their destination, resulting in communication failure. Reflectors are used to improve the communication environment and coverage area of mobile communications using high frequencies. Conventional reflectors have a specular reflective surface where the angle of incidence and the angle of reflection are equal, thus limiting the reflection range. To extend the communication range, meta-reflectors, which have a metasurface that reflects the incident wave in a desired direction, are being actively developed. A "metasurface" refers to an artificial surface that controls the transmission and reflection characteristics of incident electromagnetic waves. By periodically arranging metal patterns of approximately half-wavelength, the reflection characteristics are controlled to reflect incident waves in a desired direction. Reflect arrays have been proposed in which array elements are formed in divided regions on a substrate, and the gaps between the multiple patches constituting the array elements differ in each region (see, for example, Patent Document 1). Patent No. 5177708 This diagram shows the basic configuration of the reflector according to the first embodiment.This figure shows an example of a conductor pattern design method.This figure shows an example of a reflector design according to the first embodiment.This figure shows an example of a reflector design according to the first embodiment.These figures show the reflective characteristics of the reflector designed according to Figures 3A and 3B.This figure shows the standard deviation structure of the examples and comparative examples.This figure shows the reflective characteristics of the reflector designed in Figure 5.This figure shows the reflective characteristics of the reflector designed in Figure 5.This figure shows the reflection characteristics of a low dielectric constant reflector.This figure shows the reflection characteristics of a low dielectric constant reflector.This figure shows the reflection characteristics of a low dielectric constant reflector.This figure shows the reflection characteristics of a high dielectric constant reflector.This figure shows the reflection characteristics of a high dielectric constant reflector.This figure shows the reflection characteristics of a high dielectric constant reflector.This figure shows the reflection range of a low dielectric constant reflector with respect to frequency.This figure shows the reflection range of a high dielectric constant reflector with respect to frequency.This figure shows the relationship between the thickness of dielectric layers with different dielectric constants and the reflection bandwidth.This figure shows the relationship between the thickness of dielectric layers with different dielectric constants and their reflectivity.This figure shows the configuration and characteristics of the examples and comparative examples.This is a schematic diagram of the reflector according to the second embodiment.This figure shows the simulation results when the thickness and dielectric constant of the protective layer are changed.This figure shows an example of how to use the reflector according to the embodiment.This diagram shows an example of how a typical reflector is used. Figure 1 is a basic configuration diagram of a reflector 10 according to the first embodiment. The reflector 10 has a dielectric layer 11, a conductive layer 13 provided on the first surface 111 of the dielectric layer 11, and a ground layer 12 provided on the second surface 112 opposite to the first surface 111 of the dielectric layer 11. The conductive layer 13 includes an arrangement of a plurality of conductor patterns 131 and functions as a reflective surface of the reflector 10. This reflective surface is a metasurface that reflects the incident wave at an angle (absolute value) different from the angle of incidence. The ground layer 12 creates capacitance between the ground layer 12 and each conductor pattern 131, allowing the magnitude of the phase delay to be controlled for each conductor pattern 131. The conductive layer 13 and the ground layer 12 are not particularly limited as long as they are made of electrically conductive materials, but copper foil is preferred from the viewpoint of electrical conductivity, manufacturability, processability, and material cost, for example. The size and pitch of the conductor pattern 131 are set according to the desired reflection characteristics. Each of the conductor patterns 131 has a size suf