A three-dimensional finite-difference calculation of equivalent capacitances of coplanar waveguide discontinuities

A finite-difference method is applied to three-dimensional multilayered shielded structures containing planar waveguide discontinuities. The electric field distribution inside the shielded structure is computed, and the equivalent capacitances of the discontinuities are determined. Open-ends and gaps in various coplanar waveguides with one- and two-layer substrates as well as more complicated structures like interdigitated capacitors are examined. The calculated results are in good agreement with accurate measurements and results from other methods.<<ETX>>