Effect of Temperature and Multiple Scattering on Rain Attenuation of Electromagnetic Waves by a Simple Spherical Model

Abstract

Abstract-Specific rain attenuation is discussed from the viewpoint of numerical solution for scattering and absorption of electromagnetic waves related to dielectric spheres. Special attention is paid to the quantitative evaluations considering the change of temperature and the existence of multiple scattering effect. The analysis is based on the set of Stratton's vector spherical wave functions and its addition theorem, which lead to the simultaneous linear equations for the expansion coefficients with adaptively selected truncation numbers. Computed extinction cross sections lead directly to the specific rain attenuation, where the Weibull raindrop distribution model is used. It is discussed how the dependence of the permittivity of water on temperature and frequency affects the attenuation property. Furthermore, the effect of multiple scattering is evaluated in terms of the root mean square of attenuation deviation from the simple superposition of single scattering (Mie's) coefficients. Contrary to general belief, this deviation is the highest at around the boundary between microwave and millimeter wave bands.

RAIN ATTENUATION MODELING IN THE 10-100 GHz FREQUENCY USING DROP SIZE DISTRIBUTIONS FOR DIFFERENT CLIMATIC ZONES IN TROPICAL INDIA

“…The attenuation will be greater for horizontal polarization than the vertical polarization as the drops are spheroidal and elongated in the horizontal direction. The polarization dependent estimation of rain attenuation can be performed using point matching technique or T-matrix approach assuming realistic rain drop size distribution [21,22]. We used the spherical rain drop model with Mie scattering in our study as the disdrometer measures rain drops and rain rates assuming spherical drop shape.…”

Simulation of multiple scattering in the systems with complicated phase function

“…As an optical system the nematic liquid crystal is uniaxial with a permittivity tensor ε αβ (r) = ε ⊥ δ αβ + ε a n α (r)n β (r), (8) where ε a = ε −ε ⊥ , ε , ε ⊥ are permittivities along and across the equilibrium director and e (e) , k (j) = k 0 n (j) ,…”

“…This model includes the sum of hexagonal ice aggregates and quasi-spherical ice particles. In the problems of the radiation balance there used the phase function describing the scattering by polydisperse aerosols [6,7,8].…”

Potential interference and rain attenuation at 21.4–22 GHz downlink broadcasting satellite signals

“…To measure the effects of rain attenuation on the direct broadcasting satellite (DBS) downlink signals as well as the impact of the potential interference on the reception quality is one of the fundamental constraints (Tsolakis and Stutzman 1982;Crane 1996;Lin and Chen 2002;Mandeep 2007;Mandeep and Allnutt 2007;Panagopoulos and Chatzarakis 2007;Bahrami and Rashed-Mohassel 2008;Ojo, Ajewole, and Sarkar 2008;Ojo and Joseph-Ojo 2008;Panagopoulos 2008;Shamsan, Al-Hetar, and Rahman 2008;Serdyuk 2008;Zhu, Li, and Lou 2008;Mandeep 2009;Setijadi, Matsushima, Tanaka, and Hendrantoro 2009;Rafi Ul Islam, Rahman, Rahim, Al-tabatabaie, and Abdulrahman 2009). The electromagnetic waves, whose frequencies are above 10 GHz while propagating over a long distance, always suffer from propagation impairments that make the signal totally degraded and weak (Samuel 1993).…”