Noise Optimization for CMOS RF Balanced Mixers

Noise features of balanced CMOS RF direct downconversion mixer are examined and analyzed in this paper. Optimal port matching circuit architectures are proposed for RF, LO and output ports to improve the mixer´s performance. Based on the analysis, both a singlebalanced and a double-balanced direct down-conversion mixers are designed using a 0.18μm CMOS process, with a 1.2V power supply. With a 2.41GHz RF signal of ??30dBm driven by a 2.4GHz LO signal of ??10dBm, both mixers have shown good performance in noise figure and conversion gain. The double-balanced one is in process of fabrication through MOSIS.