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 ges 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 ges35% of PAE between 8 and 11 GHz. A 1 mm test chip of the same technology supports a VSWR-ratio test of at least 4:1 at P_{-1 dB} power compression and 10 GHz.