Time domain analysis and design of lumped element circulators

A symmetrical 3-port lumped element circulator is designed by the use of a numerical time domain method. Metallizations that are several mum high and via-holes can be modelled with high accuracy. Parasitic elements are implicitly included. Therefore, the application of the numerical time domain method allows the numerical analysis of very compact devices built by using thin film technology. The circulator performance is numerically calculated and optimized to some extend, providing valuable information about important device performances. A comparison with measured scattering parameters shows good agreement with the calculation. A technological realization of circulator devices is presented to build compact devices. This technique is mainly based on a semi-additive metallization process yielding high accuracy in reproduction of the structure containing small features and high aspect ratios