High-order approximation of wave propagation constants in a uniformly curved waveguide

Abstract

New high-accuracy approximations of the angular propagation constants of LEpm and LMpm modes in a continuously curved rectangular waveguide are derived. They are high-order asymptotic expansions that are obtained using analytical computations. The formulas can be used for both propagating modes and an arbitrary number of evanescent ones. The approximations are applicable over a broad range Of Curvature variation and a wide range of wavenumber values. They are efficient tools for the numerical solution of modal equations.