A novel circuit architecture for fourth subharmonic mixers

Abstract

A circuit topology for high-order subharmonic (SH) mixers is described. By phase cancellation of idle frequency components, the SH mixer circuit can eliminate the complicated design procedure of idle frequency circuits. Similarly, the SH mixer circuit can achieve a high port isolation by phase cancellation of the leakage LO, RF and idle frequency signals. Based on the high-order SH mixer architecture, a new Ka-band fourth SH mixer is analyzed and designed, it shows the lowest measured conversion loss of 8.3 dB at 38.4 GHz and the loss is lower than 10.3 dB in 34-39 GHz. Measured LO-IF, RF-LO, RF-IF port isolation are better than 30.7 dB, 22.9dB and 46.5 dB, respectively.