A broadband 175-245 GHz balanced medium power amplifier using 50-nm mHEMT technology

In this paper, a balanced millimeter-wave monolithic integrated circuit (MMIC) medium power amplifier (MPA) is presented. This amplifier was developed by using an advanced 50 nm metamorphic high electron mobility transistor (mHEMT) process, where a grounded coplanar waveguide (GCPW) technology and a compact cascode configuration were adopted to achieve high gain and high output power at the WR-4 waveguide band (170-260 GHz). This two-stage MPA exhibits a 13.4 dB peak measured small-signal gain at 228 GHz and an excellent 3-dB bandwidth of 33.8% from 175 to 245 GHz. Good input and output return losses with higher values than 9.8 dB and 9.3 dB were measured. At 198 GHz a maximum output power of 9.5 dBm with 7.5 dB associated large signal gain is obtained, while at 235 GHz an output power-referred 2.3-dB compression point of 6.6 dBm is exhibited. A linear output power higher than 4 dBm (at 1-dB compression point) is realized from 198 GHz to 240 GHz (19% relative bandwidth, RBW).