Characterization-oriented design of a compact GaAs MMIC 3-stacked power cell

This work discusses the design of a 3-stacked GaAs HEMT test cell at 10 GHz. The series stacked topology, well known for CMOS amplifiers, can be profitably applied to GaAs microwave monolithic integrated circuits, overcoming the limits imposed by breakdown. The stacked structure here presented, currently under fabrication, has been developed following a characterization-oriented strategy, since it aims to assess a commercial high-frequency 0.1 um AlGaAs HEMT technology through large-signal source- and load-pull characterization. The standard foundry HEMT layout has been modified to obtain a maximally compact cell and reduce transmission lines parasitic effects, thus the foundry model validity in this condition must be assessed, too. For testing purposes a relatively low operating frequency, with respect to the selected technology, has been chosen to reduce the HEMT parasitic effects. When closed on the optimum load, the cell performance at 10 GHz are output power above 27 dBm, PAE around 46% and gain above 17 dB.