Using Dataset Expressions

A dataset is a collection of data. It can take the following form:

$ds1((x0,y0), ..., (xn,yn))

Once created, a dataset (such as $ds1) may be used as the first parameter to piecewise linear (pwl, pwlx, and pwl_periodic) functions, and may also be assigned to variables, in which case the variable may be used as the second parameter to pwl, pwlx, and pwl_periodic functions.

You can generate a dataset using a series of points in a plot on the Datasets dialog box (See: Adding Datasets). Each plot consists of straight line segments whose vertices represent their end points. A curve is fitted to the segments of the plot. This curve, which best fits the segmented plot, consists of the co-ordinates used in the creation of the dataset. The dataset may then be used in the piecewise linear intrinsic functions.

Note:

The following is an example showing how to make a material property frequency dependent using a dataset as the first parameter to a pwl function. The values used are arbitrary.

  1. For a project-level dataset, click Project > Datasets. For a design-level dataset, click HFSS > Design Datasets.
  2. Click Add.
  3. Set the Name field and Coordinates as desired and click OK.

    The dataset is created.

    Dataset window with data set entered in XY coordinates

    Note:

    By default, the dollar sign ($) is assigned to a project dataset even if you do not use one while naming it.

  4. Go to Tools > Edit Libraries > Materials to open the Edit Libraries dialog box.
  5. Click Add Material.
  6. Type in the piecewise linear function and use the dataset $ds1, as shown in the following figure.

    Add Material, properties of material groupbox.

  7. Click OK.
Related Topics:

Adding Datasets

Adding a Design Variable

Editing Datasets

Using Piecewise Linear Functions in Expressions