Electromagnetic field simulation of nonlinear microstrip line by FEM

The paper presents a method for calculating the line resistance and inductance of nonlinear (normal or superconducting) microstrip lines from electromagnetic field analysis with the aid of the finite element method. Both nonlinear physical properties and geometric effects of the microstrip lines are taken into account in the basic formulation which generally results in a nonlinear integrodifferential equation for vector magnetic potential. A finite element numerical code is then developed to solve the integrodifferential equation. Illustratively, a numerical example is given to show how the nonlinear line resistance and inductance of a superconducting microstrip line can be extracted from the electromagnetic field solution