High linearity K-band InP HBT power amplifier MMIC with 62.8% PAE at 21 GHz

We report the first InP HBT MMIC power amplifier chip results at K-band. A 21 GHz fully monolithic 2 mil InP HBT power MMIC which achieves 62.8% PAE with 10 dB gain and 20 dBm output power. A higher power MMIC at 18.5 GHz achieved 25 dBm output power with 40% PAE at 1 dB compression under class AB operation with no noticeable gain expansion. The MMIC has low distortion with 3/sup rd/ order IM suppression C/I of -30.2 dBc and 5th order suppression C/I of -50.8 dBc at a combined output power of 19.3 dBm. Both amplifiers were operated under low DC power with a conservative peak current densities of <35 kA/cm/sup 2/ and a Vce of <3.3 V; showing a potential reliable application in communications.