Open-ended microstrip lines coupled through an arbitrary aperture in a thick common ground plane

The spectral domain analysis (SDA) is extended to characterize open-ended microstrip lines coupled through an aperture in a common ground plane of finite conductor thickness. In this approach, the coupling aperture is allowed to have any size, shape, and thickness. The effects of surface wave and radiation are also taken into accounts via the exact Green´s function formulation in the spectral domain. Numerical results of the S-parameters generated using this method are presented for different aperture thicknesses.