Characterization of LO leakage behavior in Transconductance Mixers

This paper presents the analysis of LO leakage behavior in transconductance mixers. LO leakage in double balanced active mixer is analyzed by simplified theoretical study and simulation. The theoretical mismatch analysis is carried out instead of a complex mixer nonlinearity analysis; this provides information about the relations of differential imbalances to actual performance. The analysis uses a number of simplifying assumptions, but without losing generality. The analysis and simulation show that the LO leakage behavior is sensitive to the mismatches in the base-band signal and any differential devices of the mixers except for the LO signal mismatch in term of duty circle time. The theoretical model result of LO leakage behavior quite agrees with the simulation result.