A low phase noise W-band InP-HBT monolithic push-push VCO

This paper reports on what is believed to be the highest frequency bipolar VCO MMIC so far reported. The W-band VCO is based on a push-push oscillator topology which employs InP-HBTs with f/sub T/'s and f/sub max/'s of 70 and 200 GHz, respectively. The W-band VCO produces a maximum oscillating frequency of 108 GHz and delivers an output power of +0.92 dBm into 50 /spl Omega/. The VCO also obtains a tuning range of 2.73 GHz or 2.6% using a monolithic varactor. A phase noise of -88 dBc/Hz and -109 dBc/Hz is achieved at 1 MHz and 10 MHz offsets, respectively, and is believed to be the lowest phase noise reported for a monolithic W-band VCO. The push-push VCO design approach enables higher VCO frequency operation, lower noise performance, and smaller size which is attractive for MM-wave frequency source applications.