Quarter wave patch antenna
US5995048A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 1997 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | May 31, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q9/0421
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An antenna design for a tag operating in an radio frequency identification system minimizes the influence of reflecting surfaces upon the antenna radiation pattern. The antenna advantageously provides near uniform performance when the tag is in varying proximity to different metal reflecting surfaces. The antenna operates as a quarter wave patch antenna and is constructed from a rectangular metal patch separated from a larger metallic plane. This metallic plane serves as the reference ground plane for a circuit attached to the antenna, with a direct short between the patch and the ground plane along one edge of the patch. The dimensions of the metal patch are selected such that one quarter of a wavelength of incident radiation forms a standing wave on the antenna. A careful choice of dielectric material and lateral dimensions determine the bandwidth of the antenna. The presence of the ground plane serves as a natural advantageous plane of isolation between energy radiated from the patch antenna and otherwise reflecting surfaces which may be brought into proximity with this antenna.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.