TE-wave penetration into finite-thickness slotted circular cylinder with lossy and lossless inner coatings

A technique is developed to study the penetration of a TE-polarized plane wave into perfectly electric conducting cylindrical cavities with multiple apertures, taking into account wall thickness and multilayered inner filling. It is based on an integral representation of the tangential electric field on the slot apertures and the Galerkin method using weighted Gegenbauer polynomials as basis functions. Extensive parametric studies are performed to reveal the main features of the penetrated field in a wide frequency range for single- and double-layer coatings of three types. In particular, the effect of geometric and material parameters on the appearance and attenuation of the cavity resonances is studied. The strongest effect of cylinder thickness on the penetrated field is observed in the vicinity of the peaks of the frequency dependence and must be taken into account, even if the thickness is small.