A 360 GHz Fully Integrated Differential Signal Source With 106.7 GHz Continuous Tuning Range in 90 nm SiGe:C BiCMOS

Commercial frequency-modulated continuous-wave (FMCW) radar systems are well-established in the frequency range up to 100 GHz, with some exceptions operating in the D-band and above. There are multiple advantages of operating at higher frequencies, such as the use of ON-chip antennas and, therefore, the omission of high-frequency substrates for frontend designs, which enables the fabrication of low-cost FR4 radar frontends. This work features a 360 GHz fully integrated signal source and breakout circuits at 90 and 180 GHz, manufactured in the 90 nm B12HFC SiGe:C BiCMOS technology. We present a 90-GHz wideband Colpitts–Clapp VCO combined with a static frequency divider for stabilization purposes, achieving a tuning range (TR) of 24.1 GHz and an output power of up to 6.43 dBm. Adding a frequency-doubling and amplification stage expands this circuit, achieving 51.7-GHz TR and up to 3.8-dBm output power. The 360 GHz signal source adds another frequency-doubling stage consisting of a wideband differential hybrid coupler for quadrature signal generation, amplifier chains, and two push–push frequency doublers, generating a pseudodifferential output signal with up to −1.8 dBm output power and a frequency TR of 106.7 GHz (29.9%).