Terahertz Signal Source and Receiver Operating Near 600 GHz and Their 3-D Imaging Application

In this article, a set of oscillators and a heterodyne image receiver operating near 600 GHz have been developed, each based on a 250-nm InP heterojunction bipolar transistor (HBT) technology and a 130-nm SiGe HBT technology, respectively. The oscillators are based on the common-base cross-coupled pushpush topology, which employed coupled-line loads for improved output power and efficiency with a small area. The measured oscillation frequency ranges of the three oscillators with different coupled-line lengths were 628-682, 556-610, and 509-548 GHz, respectively, with a tuning capability achieved with bias variation. The maximum output power and the dc-to-RF efficiency achieved with the oscillators were -10 dBm and 0.19%, respectively. The heterodyne receiver, which consists of a mixer, an IF amplifier, and an IF detector, exhibited a maximum responsivity of 469 kV/W and a minimum noise equivalent power (NEP) of 0.64 pW/Hz1/2. A transmission-mode 3-D THz tomography imaging setup was established with one of the fabricated oscillators and the heterodyne receiver employed as the signal source and the image detector, respectively. With the imaging setup, a successful reconstruction of 3-D images of a target object was demonstrated based on the filtered back-projection algorithm.

Automated summary

This article presents oscillators and a heterodyne image receiver operating near 600 GHz using InP HBT and SiGe HBT technologies, showing their performance in the terahertz range. The oscillators achieved tuning capability and high output power, while the heterodyne receiver demonstrated excellent responsivity and noise equivalent power.