HFSS15: Assigning Finite Conductivity Boundaries in HFSS-IE

A finite conductivity boundary approximates the behavior of the field at the object surface.

The finite conductivity boundary is valid only if the conductor being modeled is a good conductor, that is, if the conductor’s thickness is much larger than the skin depth in the given frequency range.

To assign a Finite Conductivity boundary:

1. Select a surface on which to assign the boundary and click HFSS-IE>Boundaries>Assign>Finite Conductivity to bring up the Finite Conductivity Boundary dialog box.

2. Do one of the following:

• Enter the Conductivity and the Relative Permeability.

• Select Use Material, click the material name button, and then choose a material from the material editor. The conductivity and permeability values of the material you select will be used for the boundary. Note that selecting a perfectly conducting material for a finite conductivity boundary triggers a validation error.

3. To specify the roughness of surfaces such as the interface between the conductor and the substrate for a microstrip line, enter a value for Surface Roughness and select the units (default, microns) from the pull down menu.

(This may be more intuitive than using a layered impedance boundary to model the effects.)

4. To specify a layer thickness, click the checkbox to enable the Layer Thickness field, and enter a value and select units..