Effects of LO harmonics and overlap shunting on N-phase passive mixer based receivers

This paper presents an overview of two loss mechanisms in multi-path passive mixers: 1) the up-conversion of harmonic images due to the square shape of the LO sampling pulses, and 2) the overlap between LO pulses. Both these mechanisms can be modeled by a shunting impedance on the mixer input and we explore two methods to mitigate their effects. We expanded a passive-mixer first receiver to N>;8 phases and characterized gain, noise and input impedance tuning range. Additionally, we included hardware to directly measure the effect of overlapping LO pulses on the gain and input impedance of these receivers. Finally, we propose a method to use integrated inductors to suppress the currents which flow when two mixer switches are on at the same time, alleviating this loss mechanism.