(12) United States Patent ao) Patent No.: Us 7,786,868 B2
Forster (45) Date of Patent: Aug. 31,2010
A radio frequency identification (RFID) device is capable of operating in multiple passive modes, in either a fully passive mode or a boosted passive mode. The device includes an RFID chip that is suitable for operation of passive RFID devices. An antenna is coupled to the chip for receiving radio frequency signals, such as those sent by a reader/detector device. In addition, the RFID device has an energy booster which may be used to boost the energy of signals received by the device, in order to enable operation at a reduced level of RF signal. The energy boost may be selectively applied in order to transform the passive RFID device into operating in a boosted passive mode. The energy booster may include a one-port transistor and an energy source that is used to power the transistor. The energy source may be a rechargeable energy source.
18 Claims, 4 Drawing Sheets