W-Band InP HBT Power Amplifiers

This letter reports on two power amplifier (PA) monolithic microwave-integrated circuits operating at W-band. The PAs use 250 nm InP HBTs and thin-film microstrip topology formed with benzocyclobutene dielectric. First PA utilizes a two-emitter finger HBT unit cell with each finger having emitter area of $0.25 \times 6~\mu \text{m}^{2}$ . Second PA power combines two HBT unit cells. Both amplifiers are single stage and utilize conjugate matching at the input and optimum power load matching at the output. The first amplifier has demonstrated saturated output power of 12.4 dBm and power-added efficiency (PAE) of 41.7% at 93 GHz. This is the highest PAE number demonstrated at W-band. Second amplifier has demonstrated saturated output power of 15.6 dBm and PAE of 21.1% at 89 GHz.