An application of higher order vector finite elements to the frequency-domain analysis of singly and doubly periodic geometries containing fine features

It is known that the finite-element method (FEM) may give rise to inaccurate results when lower order elements are applied to analyze problem geometries that contain very fine features such as narrow conducting strips or thin slots. In this letter, higher order vector finite elements are utilized to significantly improve the numerical accuracy in the case of singly and doubly periodic geometries comprising such fine features.