Research Program on the Asymptotic Description of Electromagnetic Pulse Propagation in Spatially Inhomogeneous, Temporally Dispersive, Attenuative Media

摘要

The high frequency, low power characteristics of ultrawideband/short- pulse signals exhibit uniquely promising features with applications to remote sensing of terrestrial objects from satellites, foliage-penetrating radar, as well as the study of biological tissue exposed to ultrawideband pulses. Indeed, previous studies of ultrawideband electromagnetic pulse propagation through dispersive, nonconducting media has shown the existence of a so-called Brillouin precursor whose peak amplitude only decays algebraically with propagation distance. However, materials such as the ionosphere, foliage and biological tissue exhibit conductivity. In this paper, we show that a Debye model material with static conductivity does indeed support a Brillouin precursor, but that this precursor now attenuates exponentially with propagation distance and not just algebraically. Nevertheless, we show that it is still advantageous to track the Brillouin precursor in remote sensing applications because its attenuation is less than the attenuation of exponentially with propagation distance and not just algebraically. Nevertheless, we show that it is still advantageous to track the Brillouin precursor in remote sensing applications because its attenuation is less than the attenuation of the main signal.