Critical analysis of results for a european GaN power amplifier after first iteration

This paper presents the results of the development of 2-6 GHz broadband high-power amplifiers (HPA) within the 1
^st
iteration of the European Korrigan project. The HPAs were fabricated using AlGaN/GaN high electronic mobility transistors (HEMT) and monolithic microwave integrated circuit (MMIC) technology. Two microstrip HPAs with output-stage active periphery of 4 mm and 8 mm are reported. The two-stage amplifiers were designed to be fully matched to 50 Omega input and output impedances. Based on a 0.5 mum gate-length microstrip HEMT technology, the MMICs were fabricated on a 70 mum thick SiC substrate. Under a 25 V DC bias condition the broadband amplifiers have exhibited about 18 dB small-signal gain. The 4mm-HPA delivers 10 W output power and 25% power added efficiency (PAE) in the 2-6 GHz frequency band, in continuous wave operation (CW) at Vds=25V. On the other hand, the 8mm-HPA delivers 16 W and 20% PAE in CW. In pulsed-mode, the output powers are 14 W and 25 W for the 4 mm and the 8 mm HPAs, respectively.