A set of fully integrated voltage-controlled oscillators (VCOs) in the 5-8-
GHz frequency range has been designed and manufactured in Si bipolar and Si
/SiGe-heterojunction-bipolar-transistor technology. A minimum phase noise o
f -100 dBc/Hz at 100-kHz off carrier was measured for 2-V supply voltage an
d 16 mW of power consumption. SiGe VCOs give considerably better phase-nois
e performance than Si bipolar VCOs for the technologies investigated herein
, using similar topologies.