K-band power amplifiers in a 100 nm GaN HEMT microstrip line MMIC technology

This paper presents two power amplifier MMICs which are designed for operation at K-band (19 GHz). They are realized using a 100nm AlGaN/GaN HEMT technology which, in addition to coplanar lines, supports microstrip lines to cover the needs of applications between X- and Ka-band frequencies. The presented MMICs are among the first power amplifiers designed with the microstrip library and are used to evaluate the technology's performance at K-band. Both amplifiers are single-stage designs, where one uses only a single 8×75 μm HEMT cell and the other one uses two cells with power-combining. In large-signal measurements, the amplifiers reached, respectively, peak efficiencies of 36% and 38% associated with output powers of 0.93W and 1.48W and drain efficiencies of 61% and 51%.