A new heuristic diffraction coefficient for lossy dielectric wedges at normal incidence

A new heuristic diffraction coefficient is proposed for dielectric wedges with losses. This new diffraction coefficient, based on the uniform theory of diffraction (UTD), is valid for incidence orthogonal to the edge and when losses are such that the field transmitted through the wedge can be neglected. This applicability range fits typical scenarios for urban propagation models. Our results are compared to those predicted by using the diffraction coefficients of R.J. Luebbers (see IEEE Trans. Antennas Propagat., vol.AP-32, p.70-76, 1984) and P.D. Holm (see IEEE Trans. Antennas Propagat., vol.48, p.1211-19, 2000), and the rigorous diffraction coefficient (RDC) of G.D. Maliuzhinets (see Sov. Phys. Dokl., vol.3, no.4, p.752-5, 1958). Comparisons with a diffraction coefficient derived from the finite-difference time-domain (FDTD) simulations are also presented for right angle wedges. Parallel and perpendicular field polarizations are tested. The new heuristic diffraction coefficient shows clear improvement in agreement with the RDC and the FDTD results. Moreover, the proposed diffraction coefficient is as simple to compute as Luebbers' and Holm's coefficients.