A novel compact low-power direct conversion receiver for mobile UHF RFID reader

A novel direct conversion receiver with low cost and low power is implemented in a 0.18 μm 1P6M standard CMOS process for a Mobile UHF RFID reader. A highly linear active mixer with low flicker noise and low noise active load is proposed. An efficient and low cost on-chip DC offset voltage canceling scheme is adopted with a high-input-impedance four-input OPAMP to buffer the output of the DC offset canceller (DCOC) block. The receiver has a measured input 1 dB compression point of −2 dBm and a sensitivity of −72 dBm in the presence of the large leakage signal from the transmitter. Only occupying a silicon area of 2.5 mm2 and consuming 21 mA from a 1.8 V supply, the receiver makes the mobile UHF RFID reader to communicate with a transponder in a distance of 1 m conveniently.