Analysis on The Propagation of The Electromagnetic Waves Impacted by Rough Surface Scattering Using Numerical EM Models

• Main Author: 余俊興
• Other Authors: 蔡木金
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/24454281006425909131

碩士 === 國立中央大學 === 電機工程研究所 === 87 === In the last two decades, many experimental and theoretical studi-es on propagation characteristics of UHF radio signals have been car-ried out, especially in the radio wave propagation in urban and subur-ban area. As a result, several empirical and theoretical radio wave propagation models for these service areas were developed. Most of these studies concentrate on the effects of wave reflection and dif-fraction phenomena, while the effect of electromagnetic wave scat-tering from rough surface is often ignored. But there can be signifi-cant fluctuations of signal level due to scattering in wireless commu-nications. However, no methodology exists to model those fluctua-tions. In this discussion, the received signals in wireless communica-tion systems that are impacted by the scattering mechanism of the sur-face with different roughness are analyzed. The relative importance of the coherent and incoherent scattering mechanism is related to the surface state. The coherent scattering component is dominant for a plain surface, while the incoherent component is dominant for a rough surface. Both carrier to multipath ( C/M ) and carrier to specular ( C/S ) ratios are evaluated and compared each other for differently rough surfaces.