Limitations and Implementation Strategies of Interstage Matching in a 6-W, 28–38-GHz GaN Power Amplifier MMIC

This is the authors' abstract. We don't add key points for this paper.

In this article, we summarize the theoretical matching boundaries and show the limitations they implicate for real-world amplifier design. Starting with a common schematic prototype, we investigate the question of how to realize its electrical response in a densely routed, massively parallelized layout. To that end, we develop a comprehensive study on the application of space-mapping techniques toward the design of high-power amplifiers (HPAs). We derive three reference design procedures and compare their performance in terms of convergence, speed, and practicality when laying out a densely routed HPA interstage matching network. Subsequently, we demonstrate the usefulness of the study by designing the networks of a compact three-stage eight-way wideband HPA in the Ka-band. The processed monolithic microwave integrated circuit features a 1-dB large-signal bandwidth of more than 11 GHz (a fractional bandwidth of 32.8%) and thus covers most of the Ka-band with an output power exceeding 6 W in 3 dB of gain compression. This demonstrates the highest combination of power and bandwidth to date using a reactively matched topology in the Ka-band.