A finite element-boundary integral method for cavities in a circular cylinder

The authors extend the FEM-BI (finite-element boundary-integral) method formulation for aperture antennas conformal to a cylindrical metallic surface. Formulas required for the computation of the matrix entries, excitation due to an obliquely incident plane wave, and the far-zone scattered field are given. To verify the accuracy of the finite elements used to discretize the cavity, the authors compare numerically computed resonant wavenumbers with their exact values. The percent error is within the expected bounds.<>