A higher-order finite element: Boundary integral method for electromagnetic scattering and radiation from bodies of revolution

The hybrid finite element - boundary integral method (FE-BI) is used to compute the radar cross section (RCS) and radiated fields of bodies of revolution (BOR). This is a 2.5-D problem since it allows simulations in a 2-D domain to correspond to a full 3-D object. The interior region, which corresponds to the local near-field of the scatterer/radiator is modeled with a higher-order finite element method (FEM) using interpolatory mixed node/vector basis functions. The radiation condition for the exterior region is enforced by using the method of moments (MoM) to form a boundary integral to enclose the interior region. Scattering problems are excited by a uniform plane wave which is decomposed into a superposition of cylindrical waves. Likewise, radiation problems are excited by local current sources which are decomposed into a Fourier series. For both scattering and radiation analysis each Fourier/cylindrical mode can be evaluated independently. The FE-BI method very accurately models the fields generated by any BOR. Increasing the order of the basis functions is shown to further improve the accuracy.