Interpolation procedure for cascading S-parameters to prevent aliasing

This paper describes a methodology for re-sampling S-parameters in a manner that prevents aliasing when combining multiple S-parameter sets. In high speed serial data link systems, S-parameters are often used to describe the characteristic behavior [1, 2]. A complex system may be composed of multiple subsystems. Each subsystem can be represented by one S-parameter set. There is a need to combine these S-parameter sets to obtain the model for the complete system. It is required that S-parameter data covers a specific bandwidth of interest. It is also required that the S parameter data has frequency resolution that is fine enough to prevent aliasing [3]. This means that the frequency resolution needs to be fine enough to provide a time interval long enough to cover the impulse response duration plus the reflections duration. Even though all the S-parameter data for an individual block may have appropriate frequency resolution, the same frequency resolution may become inadequate when combining them together in a cascade.