New method for the analysis of dispersion characteristics of various planar transmission lines with finite metallization thickness

It is shown that the eigenfunction weighted boundary integral equation method can be extended to analyze the dispersion characteristics of various planar transmission lines with finite metallization thickness, such as microstrip lines, conductor-backed coplanar waveguides, and micro-coplanar strip lines. The computational results clearly demonstrate the effect of finite strip thickness on the propagation properties of these transmission lines for MMICs (monolithic microwave integrated circuits). Compared with the boundary element method, the advantages of the proposed method are that all of the boundary integral equations can be set up only on the surfaces of the finite strips and the interfaces between air and dielectric subregions but not on all closed surfaces. This is because both the field functions and the eigenfunctions satisfy the regular homogeneous boundary condition, and the effect of the edge on the strip can easily be handled theoretically.<>