An E-band SiGe power amplifier with 28dB gain and 19.2 dBm output power utilizing an on-chip differential power combiner

This paper presents the design of an E-band power amplifier for high speed point-to-point communications (81-86 GHz). A four stage common emitter amplifier is designed and fabricated in a SiGe:C technology featuring 200-GHz fT heterojunction bipolar transistors. Two modules are combined using an on-chip power combiner which results in a measured saturated output power of 19.2 dBm and an output referred 1-dB compression point of 17dBm. Measurement results show a small-signal gain and a peak power-added efficiency of 28dB and 11% respectively. The PA demonstrates a figure-of-merit of 46dB which is amongst the highest reported in this frequency range. The on-chip power combiner which is separately fabricated and characterized shows a highly balanced performance with a maximum amplitude imbalance of 0.15dB across 80-90 GHz and a phase imbalance of 2 degrees across 70-90 GHz.