W-band InGaP/GaAs HBT MMIC frequency sources

W-band frequency sources using InGaP/GaAs HBTs are compared. The first is a fundamental frequency oscillator that provides 93 mW output power at 73.5 GHz in a compact (0.404 mm/sup 2/) chip, while the other is a doubled 38 GHz VCO providing 75 /spl mu/W output power and improved phase noise in a 5 times larger (2.139 mm/sup 2/) chip. The trade-offs in both of these designs are discussed. It was also found that cooling the 38 GHz VCOs to 100 K and 200 K improved the phase noise performance.