On the use of windows for accurate analysis of package interconnects

An accurate transient analysis of a package interconnect requires the modeling and analysis of conductor and dielectric losses, as well as other high-frequency effects of 3D structures. The skin effect and dispersion of interconnects are more accurately modeled in frequency domain. Consequently, the complete time-domain simulation of such a system is only possible using convolution techniques. Although the convolution method is well understood, the application of windowing for interconnect analysis is less so. In this paper, we present the practical considerations of window selection and its application to improve the accuracy of convolution simulators. We introduce the Tukey window and study the tradeoff between how smoothly a datum can be set to zero to avoid aliasing and suppress ripples and how much information tapering will discount at the edge of the window in order to obtain meaningful results. The bandlimiting effects of the Tukey window and other well-known windows are also compared. Finally, wirebond PBGA package and PCB-connector system are analyzed using the scattering parameters obtained from simulation and measurement, respectively, to verify the validity and accuracy of the method.