A novel image rejection CMOS mixer using T-structure filter

In this paper, 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 T-structure filter to suppress the image signal, leading to the improvements in the noise figure (NF) and conversion gain. An image rejection of 25-85 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 single-side band (SSB) NF of 5 dB improved by 3.4 dB. The conversion gain of 10.5 dB, improved by more than 3 dB. The circuit operates at the supply voltage of 1.8 V, and dissipates 12 mW.