Circular slot antenna
US5621419A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1995 |
| Grant date | Apr 15, 1997 |
| Priority date | — |
| Expiry date | May 23, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY04S20/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.