50 mW 220 GHz InP HBT power amplifier MMIC

In this paper, a 220-235 GHz single-stage power amplifier (PA) MMIC is presented. The amplifier uses 250 nm InP hetero-junction bipolar transistors (HBTs) and benzocyclobutene (BCB) thin-film microstrip technology. Two levels of power combining were used on-chip to achieve total emitter area of 12 μm². The first level is a two emitter finger HBT with each finger having emitter area of 0.25×6 μm². The second level is on-chip power combining of four two-finger HBTs in parallel. The amplifier MMIC has 5 dB of small signal gain from 220 to 240 GHz. It has demonstrated saturated output power of 50 mW at 220 and 225 GHz with power-added efficiency (PAE) ≥ 6.7 %. At 231 and 235 GHz, the PA demonstrates saturated output power of 40 mW and PAE ≥ 5.5 %. These are the highest PAE numbers demonstrated at these frequencies.