FEM, Electromagnetics, Center for Computational Electromagnetics, UIUC From the Univ of Illinois at Urbana-Champaign, Center for Computational Electromagnetics (development and application of the finite element method for analyzing antennas, high-frequency circuits, high-speed circuits, and so on). The governing equations are Maxwell's equations. The matrix results from the finite-element discretization of a bandpass microwave filter at 500 MHz. The first-order vector element is employed. The absorbing boundary condition is applied on the outer boundary of the structure for emulating the open space. The port boundary condition is applied on each port of the circuit for the truncating the computational domain and exciting the circuit. Due to these boundary conditions, the finite-element system matrix is complex.