Minimum Noise Figure of SiGe HBTs under Different Operation Configurations

Minimum noise figure (NF
_min
) of SiGe HBTs under common-base (CB) configuration is analyzed through noise modeling, calculation and measurements and compared with that under CE operation configuration. Results show that the two configurations have similar NF
_min
at low frequencies. At high frequencies, the CB configuration has higher NF
_min
than the CE configuration, while higher gain is exhibited by the CB configuration than the CE configuration. Tradeoff between NF
_min
and power gain ought to be considered for circuits design in employing different configurations