Packaging and thin-film truncation effects on thin-film open end microstrip line for miniature multilayer MMICs

This paper analyzes the packaging and thin-film truncation effects of the open end of thin-film microstrip lines for miniature multilayer MMICs. The formulation is implemented by the 3D finite difference method in conjunction with the higher order asymptotic boundary condition. Special treatment of mesh nodes at the corner and the fringes of the boundary is given by the interpolation. The results presented here show that (1) the field distribution is highly disturbed by the truncation of the thin dielectric film; (2) the electrical performance varies as the thin dielectric film is truncated near the open end; and (3) when a shield metal box, if any, is less than twice the thickness of the substrate, the packaging effect becomes significant