CMOS transceiver with high input dynamic range and wide modulation-depth for RFID and NFC readers

Abstract

This paper presents a fully integrated CMOS RF transceiver for radio-frequency identification (RFID) and near-field communication (NFC) readers. The receiver achieves high sensitivity using a low-noise amplifier (LNA) and enlarges the input dynamic range by employing a variable attenuator in front of the LNA. The variable attenuator is self-controlled by sensing the input signal strength with a power level detector. The transmitter incorporates a digitally controlled pulse-width modulator using a delay-locked loop to supports various amplitude-shift keying modulation depths. The transceiver is implemented using a standard 0.18-mu m CMOS process. The measurement results prove that the proposed transceiver operates successfully in both RFID and NFC modes.