High isolation sub-harmonic mixer

A thin-film prototype of a sub-harmonic diode up-converter mixer has been developed, in order to investigate the potential for achieving high 2LO to RF isolation at the circuit output port. The design, centered at 5.5 GHz LO frequency, associated with 850 MHz IF, included diode parameter extraction and simulation of the proposed circuit topology. Measured conversion losses at (2LO-IF) and (2LO+IF) show good agreement with simulated figures, and a 2LO-RF isolation higher than 50 dB was achieved.