Silicon-Germanium Voltage-Controlled Oscillator at 105 GHz

A group at UCLA, in collaboration with the Jet Propulsion Laboratory, has designed a voltage-controlled oscillator (VCO) created specifically for a compact, integrated, electronically tunable frequency generator useable for submillimeter-wave science instruments operating in extreme cold environments. The VCO makes use of SiGe heterojunction bipolar transistors (HBTs). The SiGe HBTs have a 0.13-micrometer emitter width. A differential design was used with two VCOs connected to form a quadrature signal. A 2.5-V supply is required to power the circuit. A cross-coupled CMOS pair is used for emitter-degeneration of the SiGe HBTs, and the design uses coupled load and base inductors. The circuit oscillates at 105 GHz. A linear superposition of VCOs has been designed to achieve four times the oscillation frequency of the fundamental oscillator.