Antenna apparatus for transponder
First Claim
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.
1 Assignment
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Accused Products
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.
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Citations
5 Claims
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1. An antenna apparatus comprising:
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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. - View Dependent Claims (2, 3, 4, 5)
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Specification