3D FDTD simulation of nonlinear ferroelectric materials in rectangular waveguide

Abstract

Nonlinear transmission lines (NLTLs) have numerous applications in the communications and defense industries due to their ability to form and propagate short duration, ultra wide band pulses. This paper simulates a short duration Gaussian transient exciting low order TEm, 0 modes in a nonlinear ferroelectric filled conducting waveguide. A three dimensional FDTD simulation is employed in the analysis and the ferroelectric filled waveguide model based on a nonlinear polarization relationship extrapolated from measurements. A small portion of the frequency band operates in the saturation polarization region. These terms will propagate at higher velocity than lower amplitude components and this effect counteracts dispersion and results in compression of the pulses into solitons as they propagate.