Evaluation of excess inductance of microstrip discontinuities

Excess inductance of various microstrip discontinuities is evaluated numerically, but solving an integral equation for the surface-current distribution. The equation is based on the boundary conditions for the electric field. The unknown current density is expressed in terms of an auxiliary scalar function. This function is evaluated by the method of moments, and it is approximated by linear, two-dimensional functions over a set of triangles. The excess inductance is evaluated from the resulting current distribution.