Design and characterization of a 190-GHz voltage-controlled oscillator

This paper presents a fundamental-mode voltage-controlled oscillator (VCO) for frequencies around 190 GHz fabricated in a 0.13-μm SiGe BiCMOS technology. The VCO is optimized for a mW-level output power, which is typically required for the local oscillator signal in sub-THz wireless communication systems, and for lowest DC power consumption. The conventional measurement technique for VCOs in this frequency range is improved by employing the required external subharmonic mixer within an offset phase-locked loop. Measurements of the fabricated VCO show a frequency tuning range from 184.5 GHz to 196.7 GHz and a phase noise of -91 dBc/Hz at 10 MHz offset from the oscillation frequency at 196.7 GHz. The maximum output power is -0.8 dBm at a DC power consumption of 18.2 mW. To the authors' best knowledge, the resulting power efficiency of 5.1 % is the highest reported for VCOs operating at these frequencies.