Power spectrum analysis of a tripler-based 300-GHz CMOS up-conversion mixer

A tripler-based 300-GHz-band up-conversion mixer in 40-nm CMOS is analyzed, whose operating frequency is above the unity-power gain frequency fmax. It has a common-source topology, and the intermediate frequency (IF) and the local oscillator (LO) share the same input port. To maximize the output power, the optimal ratio of IF power to LO power for linear up-conversion is identified. Measurement results are consistent with theoretical calculation.