RADIO COMMUNICATION SYSTEM

• US 20110045764A1
• Filed: 11/28/2008
• Published: 02/24/2011
• Est. Priority Date: 11/30/2007
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Furuno, Tatsuo, Maruyama, Tamami, Uebayashi, Shinji
• Granted Patent: US 8,649,742 B2
• Time in Patent Office: Days
• US Class Current: 455/7
• CPC Class Codes: H01Q 15/0086 said selective devices having materials with a synthesized negative refractive index, e.g. metamaterials or left-handed materials
• CPC Class Codes: H01Q 15/02 Refracting or diffracting devices, e.g. lens, prism
• CPC Class Codes: H01Q 15/08 formed of solid dielectric material
• CPC Class Codes: H01Q 15/14 Reflecting surfaces; Equivalent structures electromagnetic shields H01Q1/526
• CPC Class Codes: H01Q 3/46 Active lenses or reflecting arrays
• CPC Class Codes: H04B 7/145 Passive relay systems
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow

Abstract

A radio communication system according to the present invention includes a scatterer configured to reflect, refract, or transmit a radio wave radiated primarily from a transmission side apparatus to radiate the radio wave secondarily to a desired area and a metamaterial is used for the scatterer.

Claims

1. A radio communication system comprising a scatterer configured to reflect, refract, or transmit a radio wave radiated primarily from a transmission side apparatus to radiate the radio wave secondarily to a desired area,

wherein a metamaterial is used for the scatterer.

2. The radio communication system according to claim 1,

wherein the scatterer has a structure which allows the radio wave to be radiated secondarily in a direction at an angle different from a reflection angle of specular reflection.

3. The radio communication system according to claim 1 or 2,

wherein the scatterer has a structure which allows only radio waves in one or a plurality of predetermined frequency bands to be radiated secondarily.

4. The radio communication system according to any one of claims 1 to 3,

wherein the scatterer has a structure which allows the radio waves made incident to be concentrated in a direction of propagation.

5. The radio communication system according to any one of claims 1 to 4,

wherein the scatterer is formed of an EBG structure.

6. The radio communication system according to any one of claims 1 to 5,

wherein the transmission side apparatus is any of a radio base station and a mobile station.

7. The radio communication system according to claim 5,

wherein the EBG structure is formed of a periodic structure in which the radio wave made incident on the scatterer is converted into a Bloch wave.

8. The radio communication system according to any one of claims 1 to 7,

wherein a metal reflector is disposed on a back surface of the metamaterial.

9. The radio communication system according to claim 8,

wherein the system is configured so that

a radio wave having passed through the metamaterial reaches the metal reflector, and

the radio wave having reflected off the metal reflector is radiated secondarily without passing through the metamaterial.

10. The radio communication system according to claim 8,

wherein the system is configured so that

a radio wave having reached the metal reflector without passing through the metamaterial is reflected off the metal reflector, and thereafter passes through the metamaterial to be reflected secondarily.

11. The radio communication system according to any one of claims 1 to 10,

wherein the metamaterial is configured to operate in a first frequency band and a second frequency band, and

the metamaterial is configured to radiate, secondarily to the mobile station, a radio wave having been radiated primarily from the radio base station in the first frequency band and to radiate, secondarily to the base station, a radio wave having been radiated primarily from the mobile station in the second frequency band.

12. The radio communication system according to any one of claims 1 to 11,

wherein the metamaterial is formed into a shape of a polyhedron,

the system being configured so that a radio wave made incident on the metamaterial at a first incident angle is refracted in a direction at a second refraction angle by a first boundary surface, and is also configured so that

the system being configured so that a second boundary surface through which the refracted radio wave is radiated from an inside of the metamaterial to air is formed non-parallel to the first incident angle.

13. The radio communication system according to claim 4,

wherein the metamaterial has a structure in which an evanescent wave is amplified inside the metamaterial by setting an electric constant of at least any one of a permittivity and a magnetic permeability of the metamaterial to a negative value and setting a propagation constant of the metamaterial to a negative value.

14. The radio communication system according to claim 4,

wherein the metamaterial is formed of a periodic structure in which the radio wave made incident on the scatterer is converted into a Bloch wave.

15. The radio communication system according to any one of claims 1 to 14,

wherein the scatterer is formed of a reflector that controls a phase of a reflected wave of a radio wave radiated primarily from the transmission side apparatus, and

a reflection characteristic of the reflector is set in a way that the radio wave radiated primarily from the transmission side apparatus is reflected as an equiphase plane wave to be directed to a different direction from a reflection angle of specular reflection.

16. The radio communication system according to claim 15,

wherein the reflector is formed of a frequency selective reflector, and

a reflection characteristic of the reflector is set in a way that only radio waves in one or a plurality of predetermined frequency bands among radio waves radiated primarily from the transmission side apparatus are reflected as equiphase plane waves to be directed to a different direction from a reflection angle of specular reflection.