A Reflection-Amplifier-Based Long-Range Semi-Passive UHF RFID Tag With Standard Compatibility

An ultrahigh-frequency (UHF) radio frequency identification (RFID) tag structure which includes both received signal demodulation and reflected signal amplification abilities for standard compatibility is described in this letter. To let demodulation and reflected signal amplification features coexist, a simple RF switch is used to separate the reception and reflection signal paths, and a reflection amplifier (RA) is connected to one of the two RF switch paths to realize the amplified reflection state. The RF switch can guarantee good impedance matching under reception/reflection conditions; moreover, by selecting it judiciously, i.e., with a low insertion loss, it is possible to simultaneously achieve high tag sensitivity and reflection amplification. Measurement on a tag prototype has revealed a maximum read range of 96 m (with a tag sensitivity of −42 dBm) and an average power consumption of 1.134 mW.