Wideband 148-188 GHz Push-Push VCO Using Variable Inductance and Capacitance

A wideband 148-188 GHz push-push voltage-controlled oscillator (VCO) is presented. The frequency tuning is performed using a varactor, and a variable inductor optimally designed for wide inductance tuning range. At a center frequency of 168 GHz, a frequency tuning range of 40 GHz (23.8%) is achieved, which is a record value for VCOs at this frequency range. Measured minimum phase noise is -91 dBc/Hz at 1MHz offset. The fundamental and 2nd harmonic output of the VCO are connected to frequency dividers to facilitate measurements at lower frequencies and verify the correct functionality of the VCO. The chip is fabricated in a 130nm SiGe BiCMOS technology with f(T)/f(max) = 250/370 GHz.