Ultra-broadband common collector-cascode 4-cell distributed amplifier in 250nm InP HBT technology with over 200 GHz bandwidth

An ultra broadband MMIC amplifier is designed using InP double-heterojunction bipolar transistors and its on-chip measurements are reported. The multi-cell distributed amplifier uses four gain cells where each consists of a common collector input stage followed by a cascode gain stage. The chip includes bias, decoupling and terminating circuits for the dc and RF interconnects; it measures 0.72 mm by 0.4 mm. It consumes 210 mW of power and can deliver up to 5.5 dBm of output power at 195 GHz. The amplifier achieves an average gain of 13.5 dB with an overall bandwidth over 200 GHz and a ± 2 dB gain ripple. The measurements indicate that this is the widest band dc-coupled amplifier reported to date and has the highest bandwidth reported among non-cascaded distributed amplifiers.