Low phase noise Ka-band VCOs using InGaP/GaAs HBTs and coplanar waveguide

Ka-band voltage controlled oscillators (VCOs) have been designed using InGaP/GaAs HBT technology. The best measured VCO shows a phase noise of -95 dBc/Hz at 100 kHz offset and -112 dBc/Hz at 1 MHz offset, delivering 5.3 dBm output power at 40.8 GHz. Variations of circuit topology and resonator type were fabricated to evaluate their contribution to phase noise and tuning range.