Analysis of Strip-Grated Dielectric-Coated Rods by Asymptotic Strip Boundary Conditions for Studies of Dielectric Losses and Field Localization

In this paper, the surface-wave modal analysis of the transverse strip-grated dielectric-coated metal rod is done by using the asymptotic strip boundary conditions (ASBC) along with classical vector potentials in the cylindrical coordinate system. The yielded solvable system of linear equations is then cast into a homogeneous matrix equation, from which the characteristic equation as well as field distributions in explicit functional forms may be obtained. Modal dispersion diagrams and field distributions generated by this method are compared and validated with those simulated by an independent commercial full wave solver. The time cost by the ASBC method is also compared with that of the simulation software, upon which the vast superiority in speed of the proposed technique over the benchmark tool is demonstrated, but yet preserving high accuracy. Parametric studies that portray the variations of dispersion properties with various geometric attributes are carried out. Comparisons with its counterpart transverse corrugated rod are also carried out, and studies of dielectric losses are presented as well. A prototype was fabricated and measured, the experimental results of which concur well with theoretical expectations.