MWCL paper

In this letter, a millimeter-wave (mm-wave) twoway combined power amplifier (PA) is reported. It describes the first use of an interstage matching network for obtaining maximum output power from a cascode cell in the mm-wave frequency range. The PA has been fabricated in a high-speed InP double heterojunction bipolar transistor (DHBT) technology using three-finger devices. The cascode based PA has a total active emitter area of 68.4 µm2 and demonstrates a small signal gain of 9.8 dB and saturated output power of more than 18.6 dBm at 72 GHz. This corresponds to an output power density of 1.06 mW/µm2 . To the authors knowledge this represents the highest power density achieved for any InP HBT power amplifier in this frequency range.