# Defining a Dielectric

Define the first dielectric with ${\epsilon }_{\text{r}}$ = 1.5 with label Substrate1.

myDiel1 = myProject.Definitions.Media.Dielectric:AddDielectric(1.5, 0, 1000)
myDiel1.Label = "Substrate1"
1. A dielectric is an object and since there may be multiple objects in the model, it is part of the DielectricCollection.
2. Search for DielectricCollection in the Help1.
3. In DielectricCollection, under Method List, search for methods that are applicable to dielectrics:
• AddDielectric (relativepermittivity Expression, losstangent Expression, massdensity Expression)
To create the first dielectric, we will use the method:
AddDielectric(relativepermittivity Expression, losstangent Expression, massdensity Expression)
4. Fill in the values for the dielectric
AddDielectric(1.5, 0, 1000)
5. Determine the syntax to prepend to AddDielectric:
1. Since AddDielectric is a method, it is indicated by prepending a “:” (colon).
:AddDielectric(1.5, 0, 1000)
2. In the Help, under DielectricCollection > Usage locations, note the following:
Media object has collection Dielectric2

Since we know that Media is the not one of the top levels in the model tree, click Media.

In the Help, under Media > Usage locations , note the following:

ModelDefinitions object has property Media.
3. Click ModelDefinitions.
4. In the Help, under ModelDefinitions > Usage locations, note the following:
Model object has property Definitions.
Since we know that Model is the one of the top levels in the model tree, the result is then:
Definitions.Media.Dielectric:AddDielectric(1.5, 0, 1000)
5. Since the project is the highest level, we prepend our reference to the project:
myProject.Definitions.Media.Dielectric:AddDielectric(1.5, 0, 1000)
6. Add a “handle” to the dielectric:
myDiel1 = myProject.Definitions.Media.Dielectric:AddDielectric(1.5, 0, 1000)
7. Set the dielectric label to Substrate1:
myDiel1.Label = "Substrate1"
Tip: View the Dielectric (object) in the Help for a short example.
1 The API is available in the Feko Scripting and API Reference Guide (PDF) or Feko WebHelp.
2 The part that is prepended to the method, maps to the CADFEKO model tree structure.