Fundamental mode colpitts VCOs at 115 and 165-GHz

Two fundamental mode voltage controlled oscillators (VCO) at 115 and 165 GHz manufactured in a f
_T
/f
_max
=280/435-GHz SiGe Bipolar technology are presented. A differential Colpitts topology is used in both VCO designs, and the phase noise optimization is discussed. Without on-chip buffer, the 115-GHz VCO delivers -6.6-dBm output power with a 1.6-GHz tuning range and a -80 dBc/Hz phase noise at 100-kHz offset, and the 165-GHz VCO provides -15 dBm power with a 7.6-GHz tuning range and a -79 dBc/Hz phase noise at 500-kHz offset. Two VCOs consume 30 mW and 46 mW from a 3-V and a 4.6-V power supply respectively.