Transponder employing modulated backscatter microstrip double patch antenna
US5771021A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 1995 |
| Grant date | Jun 23, 1998 |
| Priority date | — |
| Expiry date | Oct 31, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01Q21/293
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A reader interrogates a transponder attached to a remote object. The transponder includes a microstrip patch antenna having two segments connected together by a switch, each segment being one-half wavelength, the antenna being a full wavelength at the frequency of the interrogating signal. In response to a control signal, the switch is opened and closed, thereby coupling and decoupling the two segments of the microstrip antenna. When the switch is in the closed position, the two segments are out-of-phase with one another, thereby producing a maximum reflected signal. When the switch is in the open position, the two segments act in concert to produce a minimum backscattered signal. The backscatter signal is thus modulated in accordance with the control signal and is received at the reader where it is subsequently decoded to identify the remote object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.