A G-band broadband balanced power amplifier module based on cascode mHEMTs

The first full G -band power amplifier module demonstrated in GaAs metamorphic high electron mobility transistor (mHEMT) technology has been developed for use as a driver amplifier in instrumentation. The circuit integrated in this module uses a compact balanced cascode topology and is based on a 35-nm mHEMT technology in a grounded coplanar waveguide environment. High compactness is achieved due to the use of a small ground-to-ground spacing of 14 mm and an advanced process with three metallization layers. The millimeter-wave integrated circuit exhibits a linear gain higher than 15.3 dB and return losses better than 10 dB from 118 to 236 GHz, which represents an ultrabroad relative bandwidth (RBW) of 67%. A peak output power of 10 dBm is achieved at 200 GHz. The WR-5 module uses broadband transitions, which show insertion losses of less than 1.5 dB. It demonstrates a small-signal gain that exceeds 13.4 dB in the whole G -band (RBW > 54%). Large-signal characterization exhibits power levels higher than 3.6 dBm from 130 to 210 GHz (RBW = 47%). This module achieves the highest bandwidth in G -band and the highest output power when comparing it with modules based on similar technologies.