A GaN on SiC process with high power density and efficiency

In this contribution, a high power density and efficiency C-Band hybrid power amplifier (PA), employing the GaN process developed at Selex ES, is presented. Thanks to technological improvements in the actual process, the current collapse and knee voltage shift problems are mitigated, showing 5W/mm power density at 20 V, with a linear output power increase as function of drain bias, up to 9.5W/mm at 35V. In order to assess the actual performances of the GaN HEMTs, the most representative active device has been characterized and modeled, and a PA at 5.5 GHz has been designed. The amplifier is designed utilizing second harmonic tuning strategy for high efficiency operation, thus exploiting the high-breakdown voltage peculiarity of GaN-based devices employing Field Plate technology. The PA shows an output power of 36.5 dBm with a power added efficiency (PAE) of 65 % and an associated gain of 12 dB while the preliminary evaluation estimate a MTTF of 10⁷h.