A SiGe Terahertz Heterodyne Imaging Transmitter With 3.3 mW Radiated Power and Fully-Integrated Phase-Locked Loop

A high-power 320 GHz transmitter using 130 nm SiGe BiCMOS technology (fT/fmax = 220/280 GHz) is reported. This transmitter consists of a 4 × 4 array of radiators based on coupled harmonic oscillators. By incorporating a signal filter structure called return-path gap coupler into a differential self-feeding oscillator, the proposed 320 GHz radiator simultaneously maximizes the fundamental oscillati...