Circular slot antenna
First Claim
1. A circular slot antenna for a radio transmitter, the antenna comprising:
- a pair of planar, generally circular, conductive members which are substantially coaxial with the parallel to each other and spaced apart to define a slot therebetween and which comprise a first disc-shaped substantially flat conductive member, conductive over substantially its entire surface area and serving as a ground plane of the antenna, and a first annular conductive member, with its outside diameter less than or equal to that of said one conductive member;
the antenna further comprising;
input means comprising an elongated conductive pillar which extends between and electrically interconnects the conductive members, a first input at a selected point along the length of said pillar, and a second input on the disc-shaped conductive member serving as ground plane of the antenna.
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Accused Products
Abstract
A radio antenna for mounting in the lid of a water meter box and forming part of a remote meter reading system comprises an annular conductive plate and a circular conductive plate which are coaxial with and parallel to each other and spaced apart to define a slot, the circular plate serving as a ground plate. The antenna has an input in the form of a conductive pillar interconnecting the two members, with a drive input at a selected point along the length of the pillar and a second input on the ground plate. A variable tuning capacitance is disposed between the plates diametrically opposite the conductive pillar. The ground plate also serves for locating the lid in undergrowth or under snow using a metal detector.
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Citations
16 Claims
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1. A circular slot antenna for a radio transmitter, the antenna comprising:
a pair of planar, generally circular, conductive members which are substantially coaxial with the parallel to each other and spaced apart to define a slot therebetween and which comprise a first disc-shaped substantially flat conductive member, conductive over substantially its entire surface area and serving as a ground plane of the antenna, and a first annular conductive member, with its outside diameter less than or equal to that of said one conductive member;
the antenna further comprising;input means comprising an elongated conductive pillar which extends between and electrically interconnects the conductive members, a first input at a selected point along the length of said pillar, and a second input on the disc-shaped conductive member serving as ground plane of the antenna. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
Specification