High-Efficiency 200-GHz Neutralized Common-Base Power Amplifiers in 250-nm InP HBT

The analysis, design, and measurement of two Indium Phosphide (InP) heterojunction bipolar transistor (HBT) power amplifier (PA) designs are presented at G-band with record efficiency. A pseudo-differential common-base (CB) stage with neutralization capacitors and low-loss coupled-line balun (CLB) improve the gain and reduce matching loss. A single-stage design achieves 8.3 to 12.7-dBm output power and 7.7 to 17.3% power-added efficiency (PAE) over 180 to 220 GHz. The use of compact baluns allows the design to occupy only 0.011mm
²
with power density of 1.69 W/mm
²
. A 3-stage, 4-way power-combined PA delivers 16.6 to 19.7-dBm output power and 6.5 to 13% PAE over 185 to 210 GHz.