5-75GHz common-gate subharmonic mixer in 65nm CMOS

Abstract

Direct conversion architectures have the advantage of no image frequencies, fewer components and lower cost. However, local oscillator (LO) leakage reduces receiver sensitivity, causes LO pulling, and is a challenging problem for direct conversion transceiver design. Proposed is a mixer using the second-order harmonic of the LO. The proposed subharmonic mixer is based on a switching common-gate structure. This mixer, built using 65nm CMOS technology, achieves measured voltage conversion gain better than 3dB for frequencies between 5 to 75GHz with a current consumption of 2mA at 1.5V power supply. In the 57 to 66GHz frequency band, the LO to RF port isolation is better than 38dB and the noise..