Numerical design strategy for lumped element circulators

A design strategy is presented for a symmetrical 3-port lumped element circulator. By applying a numerical time domain method metallisations that are several μmμm high, and via-holes can be modelled with high accuracy. Furthermore, parasitic elements are implicitly included, and the numerical analysis provides valuable information about important device performances.Therefore, the application of the presented strategy allows the numerical analysis of very compact devices built by using thin film technology.For comparison with measured scattering parameters the device performance of an optimised circulator is numerically calculated. Measured scattering parameters agree very well with the calculation results.