Controlling an RFID reader by observing a change in inductance
US7245222B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 14, 2005 |
| Grant date | Jul 17, 2007 |
| Priority date | — |
| Expiry date | Sep 6, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for controlling a radio frequency identification (RFID) reader to detect the proximity of an RFID device based on observing a change in effective inductance. The RFID reader includes an excitation signal generator and a resonant filter that combined are capable of generating and transmitting a detection signal, an RFID device detector for measuring a detector parameter indicative of the change in effective inductance, and a detection signal receiver for determining whether an RFID device is present. The method includes awakening from a detection sleep state at a preselected time, generating and transmitting a detection signal, measuring at least one detector parameter indicative of the change in effective inductance, and determining whether the RFID device is present. When the RFID device is not present, the method returns to the detection sleep state and, when the RFID device is present, the method exits the detection sleep state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.