A state-space modeling approach for dynamic nonlinear microwave system based on large signal time domain measurements

This paper introduces a model for dynamic nonlinear microwave systems or device operating in large signal regime, based on a state-space formulation. It differs from previous approaches in the comprehensive description of the describing functions and the identification procedure based on the solution of a linear system of equations. The model is able to predict specific operation states, having identified the model in an a-priory defined set of operation states. The identification procedure, as well as the validation, is based on multisine large signal time domain measurements at different input power levels. Extensive experimental results are provided for a case study based on a commercial InGaP HBT gain block driven by a set of 9 tones equally distributed in 1.6 MHz bandwidth around the frequency of 4.9GHz, with all the power levels ranging from linear to saturation regions. The accuracy of the model, also in terms of prediction capabilities is provided in both time- and frequency-domain.