Specifying Solution Settings > Setting Adaptive Analysis Parameters for HFSS       

Produce Derivatives for Selected Variables

The Derivatives feature produces derivatives of S-parameters and related matrix quantities such as Y or Z. You can select design properties and project variables as variables of differentiation. If your design has appropriate candidate variables, the Derivatives tab of the Solution setup lists them. You enable the derivative calculation by checking the appropriate boxes.

To have HFSS calculate derivatives for design or project variables:

1. Open the Derivatives tab of the Solution Setup

2. For the desired variable, click the checkbox in the Use column.

You can view the computed derivatives in the Reporter. You can also use them through the Tune Reports command for interactive exploration of small variations in the design, without the need to solve again. Furthermore, for Optimetrics, the SNLP optimizer will take advantage of the derivatives when they are available, which can reduce the number of simulations needed to find the optimum.

This feature has the following limits on use:

• HFSS Transient projects do not support derivatives.

• HFSS Eigenmode projects do not support derivatives.

• Derivatives are not computed in a ports-only solution.

• Parameters of differentiation may not affect Floquet ports.

• Parameters of differentiation many not affect deembedded Lumped ports.

• Derivatives are not supported for any solution employing Domain Decomposition Method (DDM), which includes FEBI radiation boundaries, IE Regions, Finite Arrays.

Related Topics

Setting Adaptive Analysis Parameters

Derivative Tuning for Reports

Examples: Tune a Coax Fed Patch

Technical Notes: Overview of the Technical Approach for Derivatives in in HFSS