How to Run a Sonnet Optimization with Netlist and Geometry Project Parameters

Tips and App Notes

There are cases in which you would like to run a parameter sweep or optimization involving parameters beyond a single geometry file. Examples of this would include a geometry project with associated lumped elements, and two or more cascaded geometry projects. Sonnet provides a way to accomplish this through the careful setup of a Netlist Project, which references and controls geometry subprojects.  The rest of this topic describes this procedure and discusses the key step of tying the geometry subproject parameters to the Netlist project parameters.

Step 1: Define parameters in the geometry project

For this example, we will assume that you have a geometry project with four parameters: L, S, W and O as shown below. For details about using parameters in a Geometry project, see Parameters.

Step 2: Define parameters in the Netlist project which will use the geometry project as a component.

Define parameters in the Netlist project with labels similar to those in the geometry project. For example, for Parameter L in the geometry project, you would define a parameter Net_L in the netlist project.

Step 3: Add the Project element in the Netlist project

For detailed instructions on adding a project element to a netlist, see How do I add a project element?

By default the parameters in the geometry file are presented. We need to modify these to specify Netlist parameters.

Set ”L” parameter to ”net_L” which is a parameter within the Netlist project.

Step 4:  Adding the separate Netlist parameters (Optional)

Optionally, Netlist project parameters may be set for Netlist element use only.  An example would be a modeled capacitor as shown by the parameter "C" in the illustration below. "Net_L" is the parameter which relates to the project element that uses the parameter "L."

The geometry project appears in the Netlist project with the ”L” parameter set to a Netlist parameter ”net_L”  as shown below.

Step 5: Optimization

Within the Netlist project the parameters may be setup for a parameter sweep or optimization.  For details on doing a parameterization or optimization, see Parameter Sweeps or Optimizing.

Netlist parameter values are shared with the associated geometry project, if properly setup. Shown below is the  with Optimization selected as the type of analysis, using the two parameters "net_L" and "C" for the optimization. Note that the Hierarchy Sweep option is selected. This ensures that the project element is analyzed at the same frequencies as the netlist.

When the optimization is run the parameter "L" in the subproject varies over the same data range as the parameter net_L so that the subproject is optimized for use in the netlist.