The first report of AlGaN/GaN HEMT-based voltage controlled oscillators (VC
Os) is presented. Varactor-tuned oscillators implemented using distributed
networks oscillate at 6 GHz with high output power (0.5 W), low-phase noise
(-92 dBc/Hz SSB noise at 100 KHz offset), and high-tuning bandwidth (10%),
The measured phase noise of AlGaN/GaN FETs is compared to the phase noise
of GaAs FET and GaAs HBTs at 6 GHz, indicating the AlGaN/GaN FET exhibits e
quivalent SSB noise to GaAs FETs. These results indicate high power AlGaN/G
aN-based VCOs may be used to simplify the line up in a communication radio,
while improving the overall efficiency of the radio.