Questions and Answers

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1. What is EMtoSPICE?

EMtoSPICE is a software tool that converts S-parameters to equivalent SPICE models.

2. How does EMtoSPICE compare to other similar tools?

Most of the currently existing tools have one or more of the following characteristics.

• Inability to maintain the accuracy of SPICE models over broadband frequencies.
• Further degradation of accuracy for complex-shaped curves, for example, the curves that contain many peaks, deeps, etc.
• Frequent generation of non-convegent models in time domain due to lack of stability and passivity algorithms.
• No immediate access to the accuracy of extracted models. User has no knowledge of accuracy before generating a model.
• Extracted models may contain extreme values that are not acceptable to SPICE.

EMtoSPICE incorporates breakthrough technologies that allows the following distinguished properties.

• Generation of highly accurate models over broadband frequencies.
• Generation of compact models for fast simulation.
• Immediate access to accuracy via plots and RMS errors.
• Automatic search for the optimum order within the user-specified range.
• Selective refinement of accuracy for each S-parameter (S11, S12, ..).
• Guaranteed stability and optional passivity enforcement to ensure convergence of models in time domain.
• Models only contain acceptable values and are compatible to SPICE simulators.
• Native HSPICEŽ format available. Optimized for speed in HSPICEŽ.

3. What about the SPICE simulators that accept S-parameters for transient simulation?

Such tools convert s-parameters to equivalent circuits or go through curve-fitting processes. Since they are internal processes, user has no immediate knowledge of the accuracy of the results. They may also face the other shorfalls mentioned above.

Transient analysis is very slow for the tools that perform direct convolution.

4. What is order?

Order is equivalent to the number of poles captured to approximate the S-parameter response during interpolation.

5. Can EMtoSPICE accurately curve-fit S-parameters up to 100 GHz?

There is an example of a stripline curve-fitted up to 1 THz (or 1000 GHz) using EMtoSPICE. Click HERE to view the plots.

Unlike the first generation curve-fitting algorithms that are limited to the low order modeling, the breakthrough next generation algorithms incorporated in EMtoSPICE are capable to generate models using very high order, allowing unprecedented accuracy and bandwidth that are unheard of.