HFSS15: Defining Frequency-Dependent Material Properties for Lossy Dielectrics

1. In the View/Edit Material window, click Set Frequency Dependency.

2. In the Frequency Dependent Material Setup Option window, select Loss Model Input if you are working with a lossy dielectric material with a lower frequency near DC. HFSS will enable you to specify the material’s conductivity at DC, rather than its loss tangent, and specify the high frequency/optical permittivity.

3. Click OK.

The Loss Model Frequency Dependent Material Input dialog box appears.

4. Enter a Lower Frequency value.

HFSS assumes that the material’s property values remain constant below this frequency.

5. Enter an Upper Frequency value.

HFSS assumes that the material’s property values remain constant above this frequency, unless otherwise specified for relative permittivity.

6. Under Relative Permittivity, do the following:

a. Enter the permittivity of the material at frequencies below the lower frequency in the At Lower Frequency text box.

b. Enter the permittivity of the material at frequencies above the upper frequency in the At Upper Frequency text box.

If the material does not vary with frequency, enter the same value you entered for the permittivity’s lower frequency.

c. Optionally, to specify the high frequency/optical permittivity, select At High/Optical Frequency, and then type the value in the text box.

7. Enter the permittivity of the material at frequencies below the lower frequency in the At Lower Frequency text box.

8. Under Conductivity or Dielectric Loss Tangent, do the following:

Enter either the conductivity (step a) or the loss tangent (step b).

a. If you prefer to specify the material’s conductivity at DC, rather than its loss tangent value at the lower frequency, select At DC (Conductivity), and then type the conductivity value at DC in the text box.

b. If you prefer to specify the loss tangent value of the material at the lower frequency, rather than its conductivity at DC, select At Lower Frequency (Loss Tangent), and then type the loss tangent value in the text box.

c. Enter the Upper Frequency (Loss Tangent) value of the material in the text box.

9. Click OK.

You return to the View/Edit Material window. New default function names appear in the material property text boxes.