An integral equation solution to the scattering of electromagnetic radiation by dielectric spheroids and ellipsoids

Electromagnetic Modeling of the Propagation Characteristics of Satellite Communications Through Composite Precipitation Layers, Part II: Results of Computer Simulations

“…The results are given for LP (Laws and Parsons, 1948), MMP, JT, JD (Olsen, Rogers, and Hodge, 1978) and LN RSD (Ajaya and Olsen, 1985), drop temperatures of 0 0 C and 20 0 C and frequencies from 1 to 200 GHz with an increment of 1 GHz. With the exception of the limited data presented by Oguchi (1977), Fang andLee (1978), andLi et al (1995) previous results for ∆α and ∆φ were restricted to only oblate drops (Oguchi, 1964), (Morrison and Cross, 1974), (Warner and Hizal, 1976), (Holt, Uzunoglu, and Evans, 1978), (Seow et al 1998) at a single drop temperature and for frequencies less than 100 GHz using much wider frequency increments. It should be mentioned that the perturbation approximation utilized by Oguchi (1964) and Li et al (1995) yields less accurate results, particularly for ∆φ above 30 GHz.…”

“…An important aspect of the work reported in this paper is the implementation of the GMT for the EM scattering from realistically distorted raindrops at frequencies which have not been hitherto considered by any other numerical EM computational technique including the point-matching (Morrison and Cross, 1974), (Oguchi, 1977), perturbation (Oguchi, 1964) and (Li, et al, 1995), T-matrix (Warner andHizal, 1976), integral-equation (Holt, Uzunoglu, andEvans, 1978) and the finite element method (Ajase and Sadiku, 1995). The use of the GMT not only extends the solution to encompass frequencies well above 100 GHz, but also takes a step forward in improving the accuracy, particularly of ∆φ above 30 GHz.…”

“…This dearth of published data stemmed primarily from the formidable numerical difficulties encountered in computing the scattering properties of an arbitrarily-shaped, 3-D scattering object whose size is comparable to or larger than the wavelength of the incident radiation. This is probably why most of the early (Oguchi, 1964(Oguchi, , 1977, (Morrison and Cross, 1974), (Warner and Hizal, 1976), (Holt et al 1978) and more recent investigation (Ajase and Sadiku, 1995), (Li et al, 1995), (de Wolf and Zwiesler, 1996), (Seow et al 1998) focused their efforts on frequencies less than 100 GHz. In contrast, the dispersive characteristics of ∆α and ∆φ are provided herein for rain rates from 2.54 mm/h to 152.4 mm/h, raindrop temperatures of 0 o C and 20 o C, and frequencies from 1 to 200 GHz.…”

Polarisation basis transformation of weather radar measurements in the power domain

“…To simulate the backward scattering amplitudes of raindrops, the Fredholm integral method (FIM) for dielectric spheroids was used, Holt et al (1978). All raindrops were assumed to be equally aligned with their major axis along horizontal polarisation without any canting.…”

Microwave Specific Attenuation by Oblate Spheroidal Raindrops: an Exact Analysis of TCS's in Terms of Spheroidal Wave Functions

“…The most popular raindrop model for the analysis of rainfall attenuation in the published literature usually considers the raindrops as spheroidal raindrop scatterers. The methods and techniques employed for the analysis of specific rainfall attenuation are the boundary-perturbation and point-matching techniques by Oguchi [1,2], the leastsquares fitting process of boundary conditions by Morrison and Cross [3], the sphere-based Taylor expansion by Erma [4][5][6], the integral equation technique by Holt et al [7], the T-matrix method by Waterman [8][9][10] and the method of extended boundary conditions by Warner [11,12].…”