RF/Microwave EDA Software Design Flow Considerations For PA MMIC Design

By Michael Heimlich, AWR Corporation / Macquarie University

The evolution of integrated circuit technology demands that designers in this field adapt to ever-changing manufacturing techniques driven by performance, cost, benefit, and risk demands. Today’s power amplifier (PA) designer working in solid state technologies must navigate a plethora of available processes, including gallium arsenide (GaAs), gallium nitride (GaN) and silicon carbide (SiC) pseudomorphic high electron mobility transistor (PHEMT), radio-frequency complementary metal oxide semiconductor (RF CMOS), and GaAs or silicon germanium (SiGe) heterojunction bipolar transistor (HBT), to name just a few. Similarly, different design challenges demand different amplifier classes and/or topologies like Class AB, Darlingtons, switch-mode PAs, and digital predistortion. Moving from one technology to another implies that certain skills and knowledge are transportable and transferable. 

The most basic of these skills is the effective use of electronic design automation (EDA) tools for designing the monolithic microwave IC (MMIC) itself.  More exactly, it is a strategy, design flow, or guidelines for how to start from requirements and a process design kit (PDK) and get to a point where the more complicated requirements can be tackled. In this white paper, a GaAs pHEMT PA design approach is examined from a systems perspective. It further highlights the design flow and its essential features for most PA design projects by illustrating the design of a simple, Class A GaAs pHEMT MMIC PA done with AWR’s Microwave Office® high-frequency design software. Before illustrating a detailed approach to the design, the concepts of design closure and parametric design are described as key concepts to understanding each step of the PA design process.