Interfaces

Assign properties to geometry surfaces (or directly to the mesh surfaces). The properties include the calculation technique and the electromagnetic characteristics. Before generating a mesh, a property must be assigned to all the surfaces.

Each interface has a specific name and specific properties. Create a new interface by clicking on the « New » icon :.

Define the properties of each interface, then store the information by clicking on the « Update » icon :. The following properties must be defined :

1) Electrical Surface Property :

• PC : Perfectly conducting, for all perfect metals, probably the most used interface.

• Dielectric : Boundary between 2 dielectric domains.

• Zs : Surface impedance approximation (not active in all versions, please contact IEEA for more information).

• Visu : Near field output. This surface will be meshed and all its nodes will be used as near field computation points. Such a surface doesn't physically exist.

2) Calculation technique  :

• MoM : Method of Moments, the default and most versatile method.

• PO : Physical optics. The currently implemented PO method is aimed at reflector simulation. That's why it is limited to PC surfaces and there is no shading computation (all the triangles of the reflector are visible from the feed).

Note : For a  « Visu » property, the calculation technique is ignored

3) An infinitely thin metal sheet is usually surrounded by a single medium. In that case check « Surrounded by only one medium ».

4) A metal sheet can also be on the boundary between 2 dielectric domains. This is defined by checking « Separates two media ». In that case, a additional medium field appears in order to define both media. All the media used are defined with the Media tool.

Note : A « Dielectric » surface property is always between 2 media, like in the following example :

When the interface is fully defined, assign it to the geometry surfaces (or the mesh triangles in mesh mode). This is done by using the Assign button and by selecting surfaces with the mouse. When all the wanted surfaces are selected, click on Finish (or press Esc, or use the middle mouse button).

To check if the interface properties are properly assigned, select the «Draw» button, then the interface name (or «All materials» in order to check all the interfaces) :

The displayed interface :

The expert's tip :

For a problem without dielectric surfaces, use the default Interface1. It is ready to go for pure metal structures.

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