Time domain modeling of a microwave Schottky diode

Time domain technique is introduced to demonstrate an efficient way of modeling microwave devices with non-linearity. A microwave Schottky diode, represented by a lumped model, is used in this paper to illustrate the time domain technique. A fast transition pulse is applied to the diode under zero-bias and forward-bias conditions. Reflected signals are measured using the time domain reflectometry (TDR) technique. Based on time domain analysis of the diode model as well as wave propagation on a transmission line, a set of differential equations are solved numerically and iteratively using the measured incident pulse as an enforced excitation. The lumped element values are extracted by comparing the simulated and the measured waveforms. The non-linearity of the diode are modeled accurately and efficiently using this technique. The method used demonstrates the advantages of time domain techniques over the conventional frequency domain technique in modeling nonlinear devices.