Software Speeds PA Design

Sept. 17, 2012
To satisfy the time, cost, and performance demands for the power amplifiers (PAs) required by today’s wireless applications, designers should rely on the right design automation software tools in conjunction with their own expertise.

In RF and microwave engineering, the design and development of power amplifiers (PAs) is something of a black art. In addition to years of focused engineering experience, it demands a suitable collection of test and measurement equipment. It also requires a combination of specialized and general design-automation software tools. As explained in a white paper from Amplifier Technology Ltd., “Design of High Power PAs Using RF/Microwave Software,” a combination of specialized and general design-automation software tools is now needed to cut design cycles and maximize performance.

The seven-page document begins by explaining that the RF/microwave transistors developed for demanding wireless applications have resulted in a greater need for software tools. While gallium-nitride (GaN) high-electron mobility transistors (HEMTs) offer high gain performance and have therefore attained major market share, for example, the much wider bandwidth-matching networks required by these transistors cannot be optimally designed with traditional Smith Chart and optimization techniques. In addition, demands for broadband high power and high-efficiency performance call for new and more sophisticated matching-network-synthesis techniques.

The paper provides an overview of the design of a high-power PA using RF/microwave design-automation software. The two software programs used are Ampsa’s MultiMatch Amplifier Design Wizard and AWR Corp.’s Microwave Office simulation and optimization design suite. With MultiMatch, actual frequency synthesis techniques are used for lossy and lossless matching network design. The design also can take advantage of the software’s “power parameters,” which form a load-line approach to design.

Thanks to the MultiMatch amplifier design template, the creation of schematics and layout is automated. In just a few clicks, the design can be transferred into Microwave Office. Using Microwave Office’s linear, nonlinear, and electromagnetic (EM) simulation engines, the design can be further analyzed, tuned, and optimized. The final RF layout is transferred to Altium Designer, which designs the control and power-supply circuits, followed by the full printed-circuit-board (PCB) schematics, layout, and bill of materials (BOM). The mechanical design is done using SolidWorks from Dassaulut Systems.

Amplifier Technology, Unit 5 Easter Court, Westerleigh Business Park, Yate, Bristol, UK bs37 5ys; + 44 (0) 8700 869941, FAX: + 44 (0) 8700 509249,