A numerical study of the effect of anomalously low attenuation of electric waves in a plane comb-shaped waveguide

In an earlier study (Slepian, 1981), the attenuation of electric waves in a planar comb-shaped waveguide was investigated analytically using an equivalent boundary condition of the impedance type and a dispersion equation for complex transverse wave numbers. The objective of the study reported here was to verify, by means of a numerical experiment, the conclusion of the analytical study concerning the existence of regimes with anomalously low attenuation of normal E-waves in the above waveguides. The results support the finding of the analytical study that losses in a comb-shaped waveguide can be lower than in a smooth waveguide with finite wall conductivity.