SIwave提取S参数用于Spice仿真的建议

long.yang

Setting up HFSS and SIwave for Nexxim Transient

As we learn more about the interactionsbetween HFSS and SIwave on one hand, and Nexxim’s transient solver on theother, we’ve come up with some guidelines for improving the results.

• Use Discrete Sweep rather than Fast or Interpolating.
  The algorithms used within HFSS and     SIwave to do interpolation do not preserve causality.

• Use a frequency sweep that gets as close to DC as     possible.
  You may be planning to     excite your structure with a source of limited frequency extent, but if     you’re using Nexxim’s transient solver, you’ll need a good DC point, since     DC must be solved to give transient a starting point.
  Also, since sine waves and other     ostensibly band-limited sources must start from zero for times less than     zero in Nexxim’s transient, there may be more low-frequency content than     you expect.

• Remember the signal-integrity rule of thumb, that the knee     frequency of a pulse is somewhere around 0.35/risetime to 0.5/risetime of     the signal.
  (There can be significant     energy above that point, depending on the shape of the pulse.) So a 100ps     risetime signal requires a top frequency of simulation of at least 5GHz     (and often much higher), no matter what the period of the signal is.

• Avoid dielectric materials with a constant non-zero loss     tangent; they are non-causal.
  Use     either lossless materials, or “frequency-dependent” ones.

• If you’re planning on using convolution, it’s best to use a     uniform frequency sweep.

• Eliminate any unused ports; extra ports put a burden on the     state-space fitter, particularly if you choose to enforce passivity.

suning360

学习一下，非常感谢