Improved mode model for IR wave propagation in hollow flexible waveguide and applications

The objective in this study is to continue the proposed mode model (Z. Menachem et al, Opt. Eng. vol. 41, pp. 2169-2180, 2002) in order to provide a numerical tool for calculation of the output fields and power density also in the case of flexible hollow waveguides. In this study, we supposed that the flexible toroidal waveguide consists of only two sections, having different radius of curvature (R1≠R2), in order to simplify the mathematical expressions. All the terms of the bending are taken into account in the calculations. Therefore the output fields are calculated also for intermediate radius of curvature (R =0.5 m, and R2=0.4 m) for the flexible waveguide. The longitudinal components of the fields are developed into a 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.