CURVILINEAR AND HIGHER-ORDER EDGE FINITE-ELEMENTS IN ELECTROMAGNETIC-FIELD COMPUTATION

''Edge'' type finite elements are very useful in computation or electromagnetic fields. Unlike nodal-based finite elements, they guarantee continuity of tangential components of the field variables across element interfaces while allowing discontinuity in normal components. This, in turn, eliminates the so-called spurious solutions in eigenvalue analysis in cavities. However, most of the work in this important area is done with linear, tetrahedral elements. A method for the systematic construction of first and second order ''edge'' and ''facet'' finite elements based on the nodal-based conventional elements, and their use is presented in this work. Higher order elements are also considered. Both tetrahedral and hexahedral elements are presented. These elements are intimately related to the corresponding nodal-based elements, allowing an easy implementation in existing nodal-based finite element computer programs. The elements constructed are then used for mode analyses in electromagnetic cavities. Better solutions are obtained compared to linear elements.