Time domain technique is introduced to demonstrate an efficient way of
modeling microwave devices with non-linearity. A microwave Schottky d
iode, represented by a lumped model, is used in this paper to illustra
te the time domain technique. A fast transition pulse is applied to th
e diode under zero-bias and forward-bias conditions. Reflected signals
are measured using the time domain reflectometry (TDR) technique. Bas
ed on time domain analysis of the diode model as well as wave propagat
ion on a transmission line, a set of differential equations are solved
numerically and iteratively using the measured incident pulse as an e
nforced excitation. The lumped element values are extracted by compari
ng 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 ove
r the conventional frequency domain technique in modeling nonlinear de
vices.