4 W, 7-12 GHz, compact CB HBT MMIC power amplifier

Abstract

Extremely compact, broadband, heterojunction bipolar transistor (HBT) power amplifiers (PAs) were demonstrated with excellent performance. Common base (CB) HBTs were used in three single-stage broadband power amplifier designs, 1 W, 2 W, and 4 W, covering 7 to 11 GHz. In addition, a 1-W common emitter (CE) HBT linear amplifier was studied for its intermodulation property for communication application. The CB HBT PAs show good scaling relation in output power level. The peak power added efficiency is 40% for both the 1-W and 2-W versions, and 34% for the 4-W version. The chip size is only 2.15 mm by 2.9 mm for the 4-W CB HBT power amplifier. The CE HBT PA provides 1-W saturated output power in class B operation. In class A linear operation, 0.4-W output power was achieved. A two-tone test showed that IM/sub 3/ is better than -20 dBc at 1-dB compression point. >