A hybrid finite-element-modal-expansion method with a new type of curvilinear mapping for the analysis of microwave passive devices

A hybrid finite-element-modal-expansion procedure for the three-dimensional analysis of passive microwave devices exploiting higher order vector basis functions and an innovative class of curved elements is presented. If modal expansions on ports are not analytically known, they can be numerically obtained via a preliminary two-and-one-dimensional finite-element analysis; curved triangular and tetrahedrical elements are defined by a rational Bézier mapping, which provides a remarkable increase in accuracy and flexibility over the conventional polynomial mapping without a significant increase in computational burden. Numerical results are provided to illustrate the efficiency and feasibility of the proposed technique.