Contactless characterization of electric structures with simulation models based on CT data

The manufactured size of electric structures decreases continually. This increases the accuracy requirements in the manufacturing process of such structures. Due to these deviations, the electric behaviour of the manufactured structures can vary from the intended parameters of the designed circuit. One technique of characterizing the electric behavior of such structures is by means of S-parameters. These parameters can also be used to verify the manufacturing process itself. The standard method of measuring S-parameters of electric structures involves an experimental setup utilizing a vector network analyzer equipped with special probes. However, this method is time-consuming and complicated especially for multilayer boards. In this paper, a method is used based on a CT scan of the electric structure under consideration. The actual geometry of the individual parts of such a structure is reconstructed by extracting surface data and fitting of geometric primitives. An electromagnetic field simulation with the extracted model yields the S-parameters. Experiments show that the simulated S-parameters are in good agreement with the measured once obtained via a vector network analyzer. The proposed method is not only easier to apply but also faster while maintaining accuracy.