Sand Particle-Size Distribution in Air and their Effect on Microwave Propagation
Sand Particle-Size Distribution in Air and their Effect on Microwave Propagation.
Keywords:
Keywords - Attenuation, Cross polarization, Phase shift.Abstract
Abstract- Microwave communication in southern parts of Libya may be affected by dust and sand storms. Microwave signals in AL-Joufrah region may suffer some attenuation and depolarization due to the presence of any carried particles in air. The study of electromagnetic signals propagation in microwave band through dust storm, requires knowledge of some of the electrical properties of the dust particles and climate conditions at the studied region. This required to collecting of samples of sand and dust particles, measure their concentration, particle size distribution and chemical analysis which essential to calculate the complex permittivity of samples. The main objective of this paper is to study the effect of sand and dust storms on microwave links, in this area by calculation the dielectric constant and depolarization factor of the dusty medium to estimate propagation constant and phase shift, which are needed to estimate signal attenuation and cross depolarization. In this work all the samples were collected from surface of ground to a height 9m, on the columns of the communication towers, at seven sites along the microwave link in the study region. From the calculations it was observed: The attenuation with visibility equal 8m (worst case) is serious, and approximately equal to 0.08665dB/km. Cross polarization can be serious when visibility fall below 10m over about 1km of path, and for visibility less than 50m phase shift increases rapidly with decreasing visibility..