Low return loss rugged RFID antenna
US7551140B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 2005 |
| Grant date | Jun 23, 2009 |
| Priority date | — |
| Expiry date | Apr 13, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q9/0435
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Methods, systems, and apparatuses for RFID devices, such as reader antennas, are described. A reader antenna includes a quadrature hybrid coupler, a termination element, and an antenna, such as a patch antenna. The quadrature hybrid coupler has first, second, third, and fourth ports. The first port receives an input radio frequency RF signal. The second port outputs a first RF output signal. The third port outputs a second RF output signal. The second RF output signal is shifted in phase by 90 degrees relative to the first RF output signal. The fourth port is coupled to the termination element. The patch antenna has a first point coupled to the first RF output signal and a second point coupled to the second RF output signal. The patch antenna radiates a circularly polarized RF signal due to the received first and second RF output signals. The circularly polarized RF signal may be used to interrogate tags. Furthermore, the reader antenna is integrated into a ruggedized structure that provides environmental protection for the antenna, including providing shock absorption for impacts to the antenna.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.