Quasi-static analysis of shielded microstripline by a modified boundary element method

A modified boundary element method for analyzing the shielded microstrip-like structure is presented. The boundary integral equations are derived via Green´s second identity with the adjoint fields chosen to satisfy the boundary conditions along the outside shielding conductor. Numerically, these result in a considerably reduced matrix size compared to that using free space Green´s functions as the adjoint fields. The computation time for off-diagonal element of the matrix can be decreased by taking the Maclaurin series expansion forms of the infinite sums. Results for microstrip line are found to be in good agreement with those in the literature