Some Researchers On The Electromagnetic/Optical Wave Propagation And Scattering In Complex Environment

In this thesis, according to theory of electromagnetic wave propagation and scattering in random media, emphasis is put on studying several problems of scattering from some typical random media, including scattering from inhomogeneous particles with Gaussian beam incidence, electromagnetic scattering from random fractal. rough surface and wave propagation in random continua--atmospheric turbulence. The extended Huygens-Fresnel principle is utilized to make analysis of the received intensity for beam propagation through the turbulent atmosphere. The treatment includes the effects of the turbulent atmosphere both on the laser beam as it propagates to the target and it propagates back to the receiver. It is assumed in the analysis that phase perturbation of the waves is the dominant effect due to the horizontal atmosphere turbulence. For a diffuse target, the effects of the turbulence on the mutual coherence function, mean intensity, covariance and variance of the scattering fields are studied in detail. Meanwhile, it is also assumed in the analysis that phase perturbation of the waves is the dominant effect due to the slant atmosphere turbulence and laser beam scattering from a diffuse target, the effects of the turbulence in the slant path on the mutual coherence function and mean intensity are given and discussed. The effect of the log-amplitude covariance as well as the wave structure function are considered, the effects of the turbulence on the mutual coherence function, mean intensity, covariance and variance of the scattering fields for a diffuse target are also analyzed.Finally, based on sources of the noise and interference on the backscattering ionogram obtained from the initial data detected in electromagnetic wave propagation, lots of the interference and noise are removed from the ionogram. Meanwhile, the useful signal is remedied. And this process reduced the losing of the data. The clean pictures of the echoed signal, which is obtained in this paper will provide a basis for the further data-processing.