Calculation of characteristic impedance for stripline based on planar circuit and lateral equivalent network

Stripline is a key component for MIC. Therefore, exact calculation of the characteristic impedance is important for analysis and synthesis of stripline circuit. There are many calculation methods for stripline with zero or finite strip thickness. Exact solution for zero thickness was already given by conformal transformation method, but that for finite thickness is not. So far, relatively exact solution is given by fringing capacitance method. Here, new and systematic mode analysis method is proposed, which is based on lateral equivalent network and can give more exact characteristic impedance for stripline with any thickness including zero thickness. This method is demonstrated to be valid and useful by good agreement with the exact results for zero thickness.