340-440mW Broadband, High-Efficiency E-Band PA's in InP HBT

Abstract

Two E-band (71-76GHz and 81-86GHz) solid-state power amplifiers in 250nm InP HBT are reported. The 71-76GHz PA demonstrates 13.3-16.2dB S21 gain and 33GHz bandwidth. Output power from 71-81GHz is > 360mW. At 76GHz, 439mW Pout (26.4dBm) is achieved with 12.1dB gain and 26.9% PAE - this corresponds to 1.14W/mm power density. The 81- 86GHz PA demonstrates 12.0-14.3dB S21 gain and 40GHz bandwidth. Output power from 76-86GHz is > 337mW. At 86GHz, 358mW Pout (25.5dBm) is achieved with 10.2dB gain and 23.6% PAE - this corresponds to 0.93W/mm power density. 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 InP HBT PA cells in the thin-film microstrip interconnect. This work improves upon the state- of-the-art for InP HBT and GaN HEMT E-Band SSPAs by demonstrating higher simultaneous power by 1.0- 2.0dB and large bandwidths, where PAE is > 15-20% in continuous wave (CW) operation. The size of the PA's is small, both only 1.95mm x 0.88mm.