The new Broadband Spice feature allows you to create a circuit model which is valid over a broad band. The Broadband Spice feature generates models that can be used in Spice as a "black box" representing the high frequency behavior of your project. This feature supports two output formats: PSpice and Cadence. This feature is an option to Sonnet Level 2 Basic and above.

In order to create a Spice model which is valid across a broad band, the Sonnet broadband SPICE feature finds a rational polynomial which "fits" the SParameter data. This polynomial is used to generate the equivalent lumped element circuits which may be used as an input to either PSpice or Spectre. Since the S-Parameters are fitted over a wide frequency band, the generated models can be used in circuit simulators for AC sweeps and transient simulations. Sonnet has optimized these models to be causal by using only resistors, capacitors and inductors.

Sonnet allows the user to select the output format and several other parameters to control the the creation of the model.

This graph shows the very close match between the model's output, represented by pink squares, and the original s-parameters, shown by the blue curve.