Numerical Evaluation of the Scattering of Brillouin Precursors From Targets Inside Water

In a dispersive medium excited by a wideband pulse, the appearance of the steady-state part of the propagated signal is preceded by oscillations known as precursors. Precursor fields in lossy Debye media have been shown to present a sub-exponential attenuation rate, thus becoming good candidates for applications requiring field penetration into such media. This communication aims to study the performance of a pulse consisting of two mutually delayed precursors for the detection of dielectric objects inside triply distilled water. Finite-difference time-domain (FDTD) simulations are employed to evaluate the strength of the scattered field obtained by illuminating the targets with the precursor-based pulse excitation and to compare it with other conventional alternatives, namely, Gaussian, rectangular and sinusoidal pulses.