Design of highly-efficient GaN x-band-power-amplifier MMICs

This paper describes the design and realization of efficient GaN/AlGaN MMICs for X-band frequencies (8-12 GHz) in microstrip- transmission-line-technology on 3-inch s.i.SiC substrates. Four dual-stage MMICs are designed and realized based on different bandwidth requirements between 1 GHz and 3 GHz with output power levels of 15-20 W at X-band. After optimization of field-plate architectures and driver stage size, a maximum PAE of >=40% is achieved between 8.5-10 GHz with a maximum output power of 19-23 W, and an associated power gain of 17 dB. A broadband device with 3 GHz bandwidth reaches >=35% of PAE between 8 and 11 GHz. A 1 mm test chip of the same technology supports a VSWR-ratio test of a least 4:1 at P(ind -1 dB) power compression and 10 GHz.