A >0mW SSPA from 76-94GHz, with Peak 28.9% PAE at 86GHz

Abstract

A 69.5-94.0GHz solid-state power amplifier MMIC is presented in 250nm InP HBT, where from 76-94GHz it demonstrates >200mW Pout with simultaneous >23.5% PAE, 11dB compressed gain and 694mW PDC. At 86GHz operation, 232mW Pout with peak 28.9% PAE is observed - this corresponds to 1.21W/mm linear power density. This 2-stage amplifier has a flat S21 mid-band gain of 14-15dB, and the 1dB small-signal gain roll-off is between 66-96GHz. The large-signal Psat bandwidth is between 69.5-94GHz. This SSPA utilizes a novel, compact power cell topology developed for multi-finger HBTs, which overcomes the inability of the RF output interconnects and combiners to carry the high DC bias currents required by the HBT PA cells in the thin-film microstrip interconnect. Across the 76-94GHz bandwidth, P1dB gain compression Pout is >118mW which corresponds to ≥ 14.5% PAE; this is a relevant RF operating point where higher linearity operation may be required. This work improves upon the state-of-the-art for E-, and W-Band SSPAs by demonstrating 6x higher bandwidth (24.5GHz largesignal bandwidth) while having high PAE > 23.5%. This compact approach can permit an additional 4× or 8× power combining and in-turn a monolithic 1-1.5W Pout SSPA in this 250nm InP HBT technology at Eand W-band.