With a rich set of load-pull data, power-amplifier (PA) designers can thoroughly investigate a device’s optimum capability in relation to design goals and performance targets. To fully benefit from this information, designers need an intuitive method to work with complex swept load-pull data sets. These data sets can include multiple fundamental frequencies, nested harmonic load-pull, and/or nested source- and load-pull.
As a result, PA performance becomes easy to understand across multiple operating conditions. In essence, performance can be analyzed in terms of frequency, power, and load or source impedance at the fundamental frequency and/or harmonic frequencies.
Measurements include available output power, gain, efficiency, and intermodulation-distortion (IMD) levels—essentially any performance metric that is able to be measured on a modern load-pull system. The measurements can be readily de-embedded to the current generator reference plane of the device, which is a critical consideration for any designer moving beyond the traditional reduced conduction angle classes of operation.
This article describes how load-pull data files with an independent swept parameter, such as power, can be used directly in the NI AWR Design Environment, specifically Microwave Office circuit design software. It also highlights the design of a Class J PA to show how load-pull data can complement traditional theoretical Class J analysis, thereby streamlining the design flow.