Validation of the asymptotic corrugation boundary condition for circular cylinders with dielectric filled corrugations

Abstract

The asymptotic corrugation boundary condition (ACBC) presented previously is improved in this paper by introducing in the analysis the ratio of the corrugation width to the corrugation period. The ACBC is also validated through comparisons with the exact Floquet mode expansion technique for the case of corrugated circular cylinders. Excellent agreement is obtained between the two solutions for small periods. The ACBC is actually asymptotically correct when the corrugation period approaches zero. It is also an extension of a similar asymptotic strip boundary condition (ASBC), which was previously used to analyze scattering from strip-loaded dielectric cylinders. The ACBC is based on approximating the field expressions inside the grooves of the corrugations and enforcing an asymptotic boundary condition at the interface to the outer region. It is valid in the limit at which the corrugation period is zero.