Terahertz: The Last Untapped Spectrum

There is an increasing interest in low cost THz systems for medical imaging, spectroscopy, and high data rate communication. Recent results in the lower THz frequencies (<600 GHz) suggests that a standard CMOS process can compete with compound semiconductors for some applications. In this talk, after a brief introduction to our research group at Cornell, we present a few "real" applications for the CMOS THz systems as well as a few "fake" ones. Next, we discuss major challenges in realizing these systems in CMOS. Moreover, we show several novel methods to overcome these challenges to generate mW-level powers at 300-500 GHz with relatively low noise using oscillators, amplifiers, and frequency multipliers. Finally, we show how similar approaches can result in >100 mW at terahertz frequencies using GaN HEMT devices.