If parts or the complete interconnect channel are given as S-Parameters, you must carefully inspect this data. Typically, raw S-Parameter data suffers from noise and other measurement influences. DC values are typically not available within the measured data. To cope with these issues, it is recommended to use the S-Parameter modeling tool as provided in Simulation Library Manager: Importing Models. These will allow you to obtain useful results in the Analysis Module.
S-Parameter modeling tools convert the raw data into a type of SPICE circuit. This can then be used within SI, PI and AMI Analysis tools. Also, passivity and causality can be checked, and corrected if required. The off-band behavior and the DC extrapolation can also be controlled in this type of tool. Model accuracy can be inspected, and the model generation can be controlled in detail, if required. This provides the best results for channel characterization.
Although general recommendations are not provided on the model creation process using S-Parameter modeling tools, some common issues are described below.
- DC-point extrapolation: inspect the DC-point description in the S-Parameter data. A manual DC-value correction of the given S-parameter data may yield better model results.
- Passivity enforcement: inspect passivity violations carefully. In some cases, the automatic passivity enforcement causes poor model quality. Accepting passivity violations may yield better model results. For example, at single points within the frequency range.
- Model accuracy: check that the created model is sufficiently accurate. This is done by comparing the model and raw data, regarding DC-point and the high-frequency (including off-band) behavior.
