A method for determination of equivalent dielectric constant of planar transmission lines on anisotropic substrates with dielectric overlay

The paper considers the problems of the dielectric anisotropy and determination of so-called equivalent dielectric constant of different planar transmission lines on anisotropic substrates, when they have been covered with dielectric overlays with open or shielded top surfaces. The idea is to investigate the possibilities for direct measurements of the equivalent dielectric constants for microstrip lines and coplanar waveguides by covering with thick enough dielectric overlays from the same material. A direct method has been proposed for determination of a set of three equivalent parameters of microwave substrates, applicable for more accurate 3D design of MW planar structures.