Modelling of a 4-18 GHz 6 W flip-chip integrated power amplifier based on GaN HEMTs technology

This paper reports on the design of a cascode GaN HEMT distributed power amplifier demonstrating significant improvement of the best power performances reported to date. The active device is a 8/spl times/50 /spl mu/m AlGaN/GaN HEMT grown on siSiC. The distributed power amplifier integrates 4 cascode cells capacitively coupled to the gate line for power optimization. The active part made of the 4 cascode cells is implanted on a GaN-based wafer while the distributed passive part made of the interconnection lines is implanted on an AlN substrate. Finally, the GaN-based wafer integrating the active part is flip-chipped onto the AlN substrate via electrical and mechanical bumps. The flip-chip integrated circuit demonstrates a mean gain of 10 dB and input/output matching lower than -10 dB over the 4-18 GHz bandwidth. At an input power of 29 dBm (1 db comp.), power simulations exhibit a mean output power of 37.6 dBm with a standard deviation of 0.3 dB, a power gain of 8.6 dB and 16% of PAE over the band. At an input power of 31 dBm (2 dB comp.), the distributed amplifier achieves a mean output power of 38.6 dBm, a power gain of 7.6 dB and 18% of PAE.