Direct extraction of an admittance domain behavioral model from large-signal load-pull measurements

Abstract

Look-up table behavioral models (i.e. X-parameters, Cardiff model), input drive ‘|A 11 |’ referenced, extracted directly from measurement data, provide an accurate non-linear CAD modeling solution. Typically, formulated, like s-parameters, in the travelling wave (A-B) domain, since these waves can be directly measured and controlled in the high frequency domain. However, if formulated in the admittance (I-V) domain they would provide a more robust MMIC design modelling solution supporting the capability of width and frequency scaling. Presently, no technique has been presented that allows for the extraction of admittance behavioral models directly from load-pull measurements. Previous solutions have all involved complex indirect procedures based on using an extracted (A-B) domain behavioral model and CAD simulations using voltage sources. In this paper, a new extraction approach is presented which, by including the influence of variable ‘Vii’, allows for direct extraction of admittance behavioral models. This approach has been validated on GaN devices.