Method and apparatus for sensing environment using a wireless passive sensor

摘要

A method for execution by a RFID tag includes receiving, by an antenna of the RFID tag, an RF signal from an RFID reader, where the RF signal has a carrier frequency. The method further includes determining, by a tuning circuit of the RFID tag, a received power level of the RF signal at the carrier frequency and whether the received power level compares favorably to a power level threshold. When the received power level compares unfavorably to the power level threshold, the method further includes adjusting, by the tuning circuit, the input impedance of the RFID tag by adjusting a tank circuit of the RFID tag until the received power level compares favorably to the power level threshold, where the input impedance of the RFID tag is based on one or more of impedance of the antenna and impedance of the tank circuit.