An 18-GHz 300-mW SiGe power HBT

Characteristic Influence of DC Bias on SiGe HBT Linearity and Power Gain under Different Operation Configurations

“…Due to high power gain values available from these devices, both common-emitter (CE) and common-base (CB) configurations have been used for power amplification. In particular, as the poweramplification frequencies move to higher frequency bands, the CB configuration has shown its particular superiority (e.g., higher power gain and higher power-added efficiency) in comparison to the CE configuration, as evidenced in the recent reports (2)(3)(4)(5)(6). Considering the fact that linearity is also of a great concern in linear amplifiers, we recently have investigated the linearity characteristics of the CB configuration and analytically compared the linearity characteristics between the CE and the CB configurations under equivalent bias conditions (i.e., the same base-emitter (V BE ) and the same base-collector junction voltages (V CB ) for the CE and the CB configurations) without involving impedance matching at the input/output of the devices (7).…”