Analytical explanation of different RF characteristics exhibited with common-emitter and common-base bipolar transistors [SiGe HBT example]

For the first time, the differences of RF characteristics exhibited by bipolar transistors between common-emitter and common-base configurations, under different stability conditions, are analytically elucidated. The analyses are verified with measured results from SiGe heterojunction bipolar transistors. These analyses markedly advocate that different configurations should be used at different amplification frequencies in order to maximize the RF performance potential of bipolar transistors.