The design of millimeter wave monolithic fourth-harmonic image rejection mixer

A 32-38 GHz monolithic fourth-harmonic image rejection mixer is designed with the commercial 0.15-µm pseudomorphic high electron-mobility transistor (pHEMT) process in this paper. This mixer employs a compact Marchand Balun for LO signal pump and a Lange Coupler for RF quadrature signal generation, as well as two resistive FET mixer cells which are based on the improved gate bias circuits. The chip size is minimized to 1.8 mm×1.6 mm. According to the results of the simulation, Image rejection ration (IRR) is more than 23 dB and conversion loss(CL) is from 16.5 to 20 dB in the frequency range of 32 to 38 GHz. And the high isolation, which is better than 32 dB from LO to RF, and 30 dB from 4LO to RF, can be achieved by the proposed configuration.