Calculation of diffraction coefficients of three-dimensional infinite conducting wedges using FDTD

Measures based calibration of 3D ray-tracing models in Andean outdoor environments

“…Geometría y coordenadas para aplicar difracción en bordes. Donde ϕ' y ϕ son los ángulos de incidencia y difracción y nπ es el ángulo exterior del borde, F(x) es la función de transición de Fresnel y dada por: Para calcular numéricamente la función de transición de Fresnel, se utiliza la siguiente expresión asintótica (para valores grandes y pequeños) (Anantha, Stratis, & Taflove, 1997), dada por: Se utilizó una interpolación para calcular esta función y hallar los argumentos intermedios. En la integral de Fresnel, En ( 14), N ± son los enteros más cercanos que satisfacen las ecuaciones y son los coeficientes de reflexión de la onda plana (para polarización con incidencia perpendicular o paralela al plano de incidencia) con reflexión especular desde una superficie rugosa (dado en ( 5)) para la cara 0, ángulo de incidencia ϕ', y para la cara n, ángulo de reflexión nπ-ϕ.…”

FDTD computed numerical diffraction coefficients of 3-D infinite material wedges

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IIntroduction In this paper, we apply the FDTD method of [1,2] to numerically obtain the dyadic diffraction coefficients for several infinite 3-D right-angle material wedges over a range of observation angles and frequencies. This method exploits the temporal causality inherent in FDTD modeling, as discussed in [2] for the infinite perfect electrical conductor (PEC) wedge case.

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“…This method exploits the temporal causality inherent in FDTD modeling, as discussed in [2] for the infinite perfect electrical conductor (PEC) wedge case. Fig.1 shows the 3-D geometry of the scatterer, the ray-fixed coordinate system (described in [2,3] for PEC wedges), and the coordinate system used in the FDTD model.…”

“…This method exploits the temporal causality inherent in FDTD modeling, as discussed in [2] for the infinite perfect electrical conductor (PEC) wedge case. Fig.1 shows the 3-D geometry of the scatterer, the ray-fixed coordinate system (described in [2,3] for PEC wedges), and the coordinate system used in the FDTD model. The figure shows the edge-fixed plane of incidence (i',i) and difhction (i,;); the ray-fixed coordinates for the incident field (i',4',bo') and diffracted field (;,$,bo); and the edge-fixed spherical angles made by the incident ray (Bo', @') and the diffracted ray (Po, 4).…”