Computing and Exporting Full-Wave SPICE Subcircuits

The ability to export subcircuits is an important feature of SIwave. Exporting a subcircuit allows you to perform an analysis of the structure in a circuit simulator, together with detailed nonlinear models of the drivers and receivers. You can also simulate systems comprising PCBs and packages by connecting their subcircuits together in SPICE or Spectre.

A full-wave subcircuit analysis includes full-wave effects. Frequency domain information is transferred to circuit simulators that operate in the time domain. Broadband matching of frequency responses is ensured while full-wave solution accuracy is preserved. When S-parameter data is exported to PSpice or HSPICE, an equivalent circuit is created. This circuit consists of frequency controlled voltage and current sources. When terminal S-parameter data is exported to Maxwell Spice software, a new full-wave N-port subcircuit is created.

See Full-wave subcircuits for more information on full-wave subcircuit models.

To export a solution into a full-wave SPICE subcircuit from SIwave:

  1. Click Results.
  2. From the SIwave area, select SYZ > [Simulation Name].
  3. Click Compute FWS Sub-Circuit.

    4. ndExplorer opens, and the Broadband Export Options window appears.

    ndExplorer and Broadband Export Options

  4. From the Output File field, enter a name and path for your file, or use the Browse button.
  5. From the Subcircuit Name field, type a name for the subcircuit.
  6. Check the Change output file format check box. Then use the radio buttons to select your appropriate SPICE file format. The default is HSPICE.
  7. If appropriate, select Use common ground.
  8. Use the check boxes to select your appropriate passivity, Z-fit, and renormalization options. For more information on these options, see Exporting Macro Model.
  9. Click Advanced>> to view additional options:
    • Passivity Options
    • Column Fitting Options
    • State Space Fitting Algorithm
    • Enable Relative Error Tolerance
    • Enforce Causality
    • For more information on these options, see Exporting Macro Model.
  10. Click OK.

    11. A SPICE file based on the geometry of the planes and added circuit elements exports to the specified location.

For more information, see S-Parameter Technical Notes.