Antenna unit having radio absorbing device

• US 20030020657A1
• Filed: 07/24/2002
• Published: 01/30/2003
• Est. Priority Date: 07/25/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation, Nippon Soken, Inc.
• Original Assignee: DENSO Corporation, Nippon Soken, Inc.
• Inventors: Sakamoto, Koji, Noda, Kazunobu, Fukui, Shinji, Hayashi, Akihiko, Koide, Shirou
• Granted Patent: US 6,788,255 B2
• Time in Patent Office: Days
• US Class Current: 343/700MS
• CPC Class Codes: H01Q 1/3291 mounted in or on other locations inside the vehicle or vehicle body
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40

Abstract

An antenna unit includes a substrate having an antenna device and a radio absorbing device. The antenna device, substrate and radio absorbing device are constructed of a patch device, a conductive material and ferrite, respectively. The radio absorbing device is attached to the rear surface of the substrate. The radio absorbing device reduces incoming radio wave signals to travel to the rear surface of the substrate due to reflections by surrounding metal parts.

Claims

1. An antenna unit comprising:

a substrate made of conductive material;

an antenna device mounted on one side of the substrate; and

a radio absorbing device attached to another side of the substrate.

2. The antenna unit as in claim 1, wherein the radio absorbing device is attached in at least one of corners of the substrate.

3. The antenna unit as in claim 1, wherein the radio absorbing device is attached along at least one of edges of the substrate.

4. The antenna unit as in claim 1, wherein the radio absorbing device is attached along all edges of the substrate.

5. The antenna unit as in claim 1, wherein the radio absorbing device is constructed of radio absorbing materials.

6. The antenna unit as in claim 1, wherein the radio absorbing device is a radio absorbing material covering an entire surface of the substrate.

7. The antenna unit as in claim 1, wherein the antenna unit is installed in a vehicle.

8. The antenna unit as in claim 1, wherein the antenna unit is installed inside a dashboard of a vehicle.

9. The antenna unit as in claim 1, wherein the antenna unit is any one of a global positioning system antenna, an antenna for a vehicle information and communication system and an antenna for the electronic toll collection system.