1-Watt Conventional and Cascoded GaN-SiC Darlington MMIC Amplifiers to 18 GHz

A 0.2 mum T-gate GaN-SiC HEMT technology with fT-70 GHz are used to achieve GaN Darlington MMIC Amplifiers with bandwidths up to 18 GHz. Both conventional Darlington and Cascoded-Darlington feedback designs were fabricated and measured. The Darlington Cascode obtains 14.7 dB gain and a bandwidth of 0.05-12.3 GHz. The conventional Darlington obtains 11 dB gain and a record 0.05-18.7 GHz multi-decade bandwidth for a GaN Darlington. These are the highest BWs reported for GaN Darlington MMIC amplifiers. In addition, P1dB ~1 Watt and > 40 dBm OIP3 was obtained beyond 4 GHz. To our knowledge, these results represent the widest bandwidths so far demonstrated for fully monolithic GaN Darlington MMICs.