Calculation of Microwave Attenuation Effect Due to Charged Sand Particles
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Calculation of Microwave Attenuation Effect Due to Charged Sand Particles Q. F. Dong & J. D. Xu & Y. L. Li & H. Zhang & M. J. Wang
Received: 7 December 2009 / Accepted: 18 November 2010 / Published online: 1 December 2010 # Springer Science+Business Media, LLC 2010
Abstract Based on the forward scattering amplitude function for charged sand particles under the Rayleigh approximation and the effective permittivity method, a calculation model for microwave attenuation due to charged sand particles is given in terms of equal sized distribution and lognormal size distribution, and the attenuation is calculated and analyzed. The results show that the attenuation with charged sand is greater than the case of no charge, and the more concentrative the surface charges on sand particles are, the greater are the influences on microwave attenuation. When the frequency is not too high, natural sand and vehicular sand have little effect on microwave attenuation, whereas the attenuation of explosive sand need be considered. Keywords Microwave . Dielectric constant . Water percent . Attenuation . Charged sand particle
1 Introduction The effects of wind-blown sand transport and sandstorms on electromagnetic signals have attracted much attention in recent years. When a sandstorm occurs, sand particles can rise to a level high enough above ground, where they remain in contact with a microwave or millimeter-wave radio path and generate the scattering and absorption effect, with the result that the signal energy is attenuated and an additional phase shift is induced. The results are a greatly reduced communication coverage, a quality degradation of communication, or even that the communication is interrupted in some areas [1]. People noticed the effects of sand and dust particles on electromagnetic signals long time ago. As reported by the review of Bashir and McEwan [2]: In 1941, Ryde and his Q. F. Dong (*) : J. D. Xu The Electronic Information Institute, Northwestern Polytechnical University, Xi’an 710072, China e-mail: [email protected] Q. F. Dong : Y. L. Li : H. Zhang : M. J. Wang Xianyang Normal University, Xianyang 712000, China
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J Infrared Milli Terahz Waves (2011) 32:55–63
companions analyzed the effects of a sandstorm on radar albedo and pointed out that when the frequency was not more than 30 GHz, the sandstorm with a low concentration had no influence on the radar signal. Sudan, Iraq and Saudi Arabia had tested and studied the microwave attenuation caused by the sandstorm in microwave path in the 1990s. Since the 1980s, China also has started the research in this respect [3–7]. Because the physical characteristics of sand particles have greater influences on the radio wave propagation, Christiand and his companions have studied the microwave dielectric constant of the dry and wet sand particles separately and discussed some existing models [8, 9]. Many measurements and theories show that sand particles carry charges, and the charges obviously influence the saltation of sand particles [10]. Considering a single s
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