Studies on cross-over and broadside-coupled microstrip lines for bandstop application

Two kinds of multilayer microstrip line structures are studied: orthogonal cross-over and broadside-coupled microstrip lines. The equivalent circuit for each two-layer element is derived by an efficient quasi-static analysis method. Combined with vias from the bottom strip to ground, these structures are employed to design bandstop filters. Numerical simulation and measurement results show the validity of the proposed structures and their CAD models in the design of bandstop filters. The proposed structures may find applications in multilayer filter designs.