A CMOS passive mixer-first receiver front-end for UHF RFID Reader

A CMOS passive mixer-first receiver front-end for UHF RFID Reader is presented in this paper. Instead of LNA input structure, we choose single-balanced passive mixer as the input stage to improve compression point, and can handle the large jammer noise from the leakage of the transmitter. The transimpedance amplifiers are followed by the mixers to provide enough gain and suppress the noise behind. We also use complex impedance match at baseband to control the real and imaginary part of the antenna equivalent impedance. This can leave out the matching network off chip. The receiver front-end circuit is designed in SMIC 0.13µm CMOS process.