Behavioural modeling of microwave oscillating amplifiers

The problem of deriving, from experimental data, a behavioral nonlinear model capable of predicting the dynamical response of microwave oscillating amplifiers (either continuous-wave or pulsed) is addressed. Experimental results are reported, showing that a good simulation accuracy can be combined with an excellent computational efficiency by resorting to a black-box modeling approach in the stroboscopic time domain, in which the oscillating amplifier is described by an algebraic-differential set of fundamental frequency phasor equations that can be considered as a "three-port" extended Van der Pol (3P-E-VdP) model of the embedded synchronized oscillator. An additional advantage of the proposed behavioral approach over standard, detailed, equivalent circuit modeling techniques is the small number of unknown model parameters that have to be identified and the fact that their values can be rather straightforwardly extracted from experimental data obtained from conventional microwave measuring apparatus.