Antenna apparatus for transponder

• US 20080001842A1
• Filed: 05/30/2007
• Published: 01/03/2008
• Est. Priority Date: 06/30/2006
• Status: Active Grant

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Konno, Yasuhiro, Shigihara, Makoto
• Granted Patent: US 7,453,415 B2
• Time in Patent Office: Days
• US Class Current: 343/872
• CPC Class Codes: B60C 23/0494 Valve stem attachments positioned inside the tyre chamber
• CPC Class Codes: H01Q 1/2241 used in or for vehicle tyres
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

An antenna apparatus is mounted at a wheel rim as a transponder of a system for monitoring a tire pressure or the like, and attached at an end portion of an air valve. The apparatus includes a circuit board having an electronic circuit portion and a grounding conductor layer, a sheet-metal inverse-F type antenna element, a sheet-metal shield case conducting to the grounding conductor layer to cover the electronic circuit portion, and a resin case for accommodating these components. One side surface extending in a longitudinal direction of a space defined between the circuit board and the radiating conductor of the antenna element faces one of sidewalls of a tire, and the other side surface thereof faces a wall surface of the wheel rim with a distance interposed therebetween, the distance being about one-fourth of a wavelength of a radio wave to be used.

Claims

1. An antenna apparatus comprising:

a circuit board having an electronic circuit portion provided on one surface thereof and a grounding conductor layer provided on the other surface thereof;

an antenna element mounted at the other surface of the circuit board;

a shield case formed by sheet-metal processing and conducting to the grounding conductor layer to cover the electronic circuit portion at the one surface of the circuit board; and

a resin case for accommodating the circuit board, the antenna element, and the shield case, the resin case being attached to an end portion of an air valve provided at a wheel rim of a tire of a vehicle,

wherein the antenna element includes a radiating conductor disposed substantially parallel to the grounding conductor layer, a feeding conductor extending from the radiating conductor toward the circuit board and connected to the electronic circuit portion, and a grounding conductor extending from the radiating conductor toward the circuit board and connected to the grounding conductor layer, and a posture of the antenna element in the resin case is determined such that one side surface extending in a longitudinal direction of a space defined between the circuit board and the radiating conductor faces one of sidewalls of the tire.

2. The antenna apparatus according to claim 1, wherein the other side surface extending in the longitudinal direction of the space defined between the circuit board and the radiating conductor faces a wall surface of the wheel rim with a distance interposed therebetween, the distance being about one-fourth of a wavelength of a radio wave to be used.

3. The antenna apparatus according to claim 1, wherein the antenna element is formed by sheet-metal processing, and the feeding conductor and the grounding conductor are formed as bent pieces extending toward the circuit board from an end portion in a longitudinal direction of the radiating conductor made of a metal plate.

4. The antenna apparatus according to claim 1, wherein the antenna element is formed by sheet-metal processing, and the feeding conductor and the grounding conductor are formed as bent pieces extending toward the circuit board from a center portion in a longitudinal direction of the radiating conductor made of a metal plate.

5. The antenna apparatus according to claim 1, wherein the resin case has an attachment protrusion to be inserted and pressed to an air hole of the air valve and fixed thereto.