High LO-RF isolation of zero-IF mixer in 0.18 mu m CMOS technology

摘要

In this study, we introduce a zero-IF sub-harmonic mixer with high isolation in the 5 GHz band using 0.18 mu m CMOS technology. Placing an LC-Tank between the class AB stage and the mixer core improves the isolation between the LO to RF at low supply voltage. The measured isolation is 48 dB between the LO and RF ports, and the 9.5 dB conversion gain is achieved with a supply voltage of 7 mA at 2.5 V. In order to alleviate the degradation of linearity due to the high conversion gain, we adopt the class AB stage as RF input stage. The measured IIP3 is -7.5 dBm.