Automated Cardiff Model Complexity Identification and Parameters Extraction From Measured Tailored A-Pull Data

This paper presents a novel experimental technique for automatically identifying the complexity and coefficients of a Cardiff behavioral model of a microwave transistor using a conventional, narrowband active load-pull system. The method ensures the accuracy of the extracted model while eliminating the need for expert human judgment/intervention. The paper details the solutions adopted to overcome the technical challenges of implementing A-pull using a narrowband vector network analyzer-based load-pull system. Specifically, to ensure that the A-pull grid is achieved quickly and accurately, and that it covers a meaningful and safe operating space for the device under test. A gallium nitride (GaN) microwave transistor is characterized and modeled to demonstrate the technique at 2.45 GHz. Results clearly show how the model complexity is automatically identified and accurate coefficients extracted. In addition, the paper demonstrates how to use this approach to allow for a systematic reduction in the number of measured load points without compromising model accuracy, further improving the process’s speed.