Derivation of equivalent circuits for via holes from full wave models

In recent work equivalent circuit elements based on the scattering (S) parameters of a microstrip via hole calculated using the finite difference time domain (FDTD) method have been optimised. Now the authors use the integral form of the full wave/finite difference frequency domain (FDFD) method incorporating losses to fit measured values for the via. For a triplate via structure a four element equivalent circuit is proposed, whose values are fitted up to 18 GHz for excellent S-parameter agreement with FDFD results.