Radiation loss in dielectric waveguide structures by the volume current method

The volume current method (VCM) is used to evaluate the radiation loss of dielectric waveguide structures. This perturbation technique is applicable to practically any waveguide structure. The radiation loss of two- and three-waveguide coupled wave structures is calculated. The theory leads to design criteria for the minimization of the radiation loss of these structures. The problem of radiation loss in bent waveguide is solved with the new formulation. Some properties of radiation from a bend are described. The expression for the bend-loss reduces to that in the literature.