A novel LC T-structure filter integrated with CMOS mixer for image rejection

A new image rejection mixer in heterodyne architecture for 2 GHz band applications based on 0.18 /spl mu/m CMOS technology is presented. The designed mixer uses a LC T-structure filter to suppress the image signal, leading to improvements in the noise figure (NF) and conversion gain. An image rejection ratio of 25-52 dB is obtained in a 150 MHz of bandwidth from 1.95 to 2.1 GHz with IF varying from 200 to 350 MHz. The simulation results show the single-side band (SSB) NF of 3.2 dB improved by 2.4 dB and the conversion gain of 13.4 dB improved by more than 1.4 dB. The circuit operates at a supply voltage of 1.8 V and dissipates 12 mW.