An improved RF front-end of UHF RFID

The circulator is usually used in UHF RFID front end circuit to isolate the leakage from Tx to Rx, however, due to the insufficient of the circulator in isolation, there is still a lot of CW signal leaking into the Rx circuit inevitably. LNA is abnegated in order to prevent the demodulator from saturation, which will degrade the receive sensitivity and the dynamic range of the receive circuit. A case that can increase the isolation was proposed, which can also upgrade the architecture of the Rx. A design of LNA was simulated and accomplished in the basement of UHF RFID practice.