High efficiency and high linearity microwave power amplifiers based on ultra-high f/sub max/ selective buried sub-collector (SBSC) HBTs

This paper presents several microwave power amplifier designs that promise high power and broad bandwidth, while meeting the efficiency and linearity requirements of advanced radar and communication systems. Power amplifiers are designed based on an ultra-high f/sub max/ (>450 GHz) selective buried sub-collector (SBSC) HBT technology. SBSC HBTs are fabricated on pre-patterned sub-collector mesas. The active device region is carefully designed so that the overlap between the extrinsic base and the sub-collector is totally eliminated for minimizing the base collector capacitance and maximizing the device f/sub max/. Simulations on SBSC HBT microwave amplifiers show that >10 W output power may be achievable with PAE>50% and OIP3=40 dBm at 7-11 GHz (X-band) and >4 W output power with PAE=30% and OIP3=32 dBm at 28-32 GHz (Ka-band). These results show the great potential of using SBSC HBTs for broadband and high power microwave amplifiers with high efficiency and linearity.