MODE MODEL FOR INFRARED PROPAGATION IN A TOROIDAL TYPE OF WAVEGUIDE AND APPLICATIONS

An improved approach is derived for the propagation of electromagnetic (EM) fields along a curved dielectric waveguide. The objective is to develop a mode model to provide a numerical tool for the calculation of the output fields also for intermediate radius of curvature (R ≈ 0.5 m). Therefore, we take into account all the terms in the calculations, without neglecting the terms of the bending. The longitudinal components of the fields are developed into Fourier-Bessel series. The transverse components of the fields are expressed as functions of the longitudinal components in the Laplace plane and are obtained by using the inverse Laplace transform. The separation of variables is obtained by using the orthogonal relations. The metal boundaries of the waveguides are modeled as a lossy dielectric media. This model is applicable for hollow waveguide tubes where the wall of the bore is covered with a metal layer and dielectric overlayer