A 220-GHz Active Down-Conversion Mixer Based on 0.1-μm GaAs pHEMT Technology

Terahertz (THz) mixers play a paramount role in high-speed communication and high-precision detection, yet are constrained by the typical need for advanced fabrication technologies and high-power THz local oscillator (LO) pump sources. This article presents the design and implementation of a single-ended subharmonic down-conversion mixer, leveraging a gate-pumped topology that operates with low LO input frequency and power requirements. The monolithic microwave integrated circuit (MMIC) of the mixer is fabricated in a 0.1- $\mu $ m gallium arsenide (GaAs) pseudomorphic high-electron-mobility transistor (pHEMT) technology and mounted to form a module. The mixer module exhibits a 3-dB radio frequency (RF) bandwidth (BW) of approximately 26 GHz, covering the range from 206 to 232 GHz. The performance supports the down-conversion of a 12-Gb/s optoelectronic THz communication system, offering a promising solution for cost-effective broadband THz converters.