A High Performance Complementary SiGe HBT Power Amplifier with a Three Conductor Coupled Line Four-Way Wilkinson Combiner Balun for Emerging K-Band LEO SATCOM Transmit Front-End IC

This work reports first a high performance (HP) complementary SiGe (CSiGe) HBT K-band power amplifier (PA) for emerging LEO SATCOM. A HP PNP SiGe HBT, with fT/fmax of 210/240 GHz, is adopted to the PA output stage for its large voltage excursion while a high speed (HS) NPN SiGe HBT at fT/fmax of 400/400 GHz is utilized for the PA driver stage. To further boost its output power (POUT), a compact three conductor coupled line (TCCL) four-way Wilkinson combiner balun (WCB) is proposed. Fabricated in 0.13 µm CSiGe BiCMOS, the proposed PA at K-band shows measured peak POUT and PAE of 26.0 dBm and 35.5% at 18.0 GHz, respectively, with the highest power density of 2010 mW/mm². The PA delivers linear POUT of 20.5/20.2 dBm at 250/400 MHz symbol rates 64 QAM modulation. This CSiGe PA result provides a blueprint for the future of low cost, HP LEO SATCOM transmit (TX) front-end IC.