A high performance V-band monolithic quadruple sub-harmonic mixer

In this paper, we present a high performance V-band quadruple sub-harmonic mixer monolithic circuit which is designed and fabricated for the millimeter wave down converter applications. While the typical sub-harmonic mixers use a half of fundamental frequency, we adopt a quarter of the fundamental frequency. The proposed circuit is based on sub-harmonic mixer with APDP (anti parallel diode pair). Upon the typical mixer design, additional stubs are placed with the modification of original stub length. And the 0.1 /spl mu/m pseudomorphic high electron mobility transistors (PHEMTs) providing better gain are positioned to each port. Used lumped elements at IF port, it provides selectivity of IF frequency, and increases isolation. Maximum conversion gain of 0.8 dB at a LO frequency of 14.5 GHz and at a RF frequency of 60.4 GHz is measured. Both LO-to-RF and LO-to-IF isolations are higher than 40 dB. These conversion gain results and isolation characteristic are the best performances reported among the quadruple sub-harmonic mixers operating in the V-band millimeter wave frequency thus far.