Working with Variables > Defining an Expression       

Using Dataset Expressions

In the simplest sense a dataset is a collection of data. It can take the following form:

$ds1((x₀,y₀), ..., (x_n,y_n))

A dataset (such as $ds1) once created may be used as the first parameter to piecewise linear (pwl 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 and pwl_periodic functions.

A dataset is generated using a series of points in a plot on the Datasets dialog box. 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 thus created may be used in the piecewise linear intrinsic functions.

1. Click HFSS> Design Datasets

2. Click Add and set the Name field and Coordinates as desired and click OK.

The dataset is created.

3. Go to Tools>Edit Configured Libraries>Materials to open the Edit Libraries dialog box.

4. Click Add Material.

5. Type in the piecewise linear function and use the dataset $ds1 as shown in the figure below.

6. Click OK.

Thus the example shows how to make a material property frequency dependent using a dataset as the first parameter to a pwl function.

Related Topics

Adding Datasets

Adding a Design Variable

Modifying Datasets

Using Piecewise Linear Functions in Expressions