Arjith Chandra Prabhu’s research while affiliated with University of Wuppertal and other places

This letter presents a 206.5–220.5-GHz fundamental differential Colpitts oscillator in a cascode topology implemented in a 130-nm SiGe HBT technology with f _t / f max of 350/450 GHz. Base inductors at the common-base (CB) stages are used to provide an inductive load at the output of the common-emitter (CE) stage, hence, boosting the output power by 27%. The resonant tank is embedded straight on top of the devices, reducing layout parasitics and resulting in a compact and efficient oscillator core layout. The oscillator provides a peak output power of 7 dBm at 208 GHz, 7.4% peak dc-to-RF efficiency at 220 GHz, and 6.55% tuning range (TR). At peak efficiency, the oscillator delivers an output power of 5.7 dBm with 50-mW dc power consumption and a phase noise (PN) of -90.2/-110 dBc/Hz at 1-/10-MHz offset, respectively. To the best of the authors’ knowledge, the presented oscillator has the best PN figure-of-merit (FoM) of -182.1 dBc/Hz at 1-MHz offset in a SiGe/CMOS technology above 200 GHz. It occupies a total area of 0.086 mm², including the RF pad, and an ultracompact core size of 0.0049 mm².

Terahertz (THz) light-field imaging offers a solution for material identification and imaging of opaque objects. This paper explores THz techniques, including coherence-based approaches and light-field methods, showcasing experimental setups and results.