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Classical theories such as the uniform theory of diffraction use analytical expressions for diffraction coefficients. These methods are convenient for canonical problems and objects much greater than the wavelength and enable to rise in frequency. For more complex and smaller scattering structures, rigorous methods as the finite difference time domain method is more suited. In this article, we present a new look on radiowave propagation prediction, combining the advantages of these two complementary methods. This article presents several studies aiming to evaluate the validity domain of this hybrid method in terms of far-field propagation conditions. Finally, an application to indoor channel modeling is presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1312–1320, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22431 [ABSTRACT FROM AUTHOR]

Wave coupling in the coupling section of a dielectric optical waveguide is discussed using even- and odd-mode analysis. The dispersion relations of different modes were obtained by solving Maxwell equations. The two-dimensional finite-difference in time-domain method was implemented to solve these equations. The even and odd modes were characterized by applying different excitation sources. A large number of time steps were taken to reveal the fine structure of the propagation modes. The propagation constants of these modes at the coupling frequency were calculated, and the optical-coupling length was determined. The result is in good agreement with those obtained by the Marcatili method. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 234–237, 2000. [ABSTRACT FROM AUTHOR]