Frequency Dependent Loss

Sonnet allows you to write your own frequency-dependent equations, or use a lookup table for any of the parameters defining a dielectric. For example, you could write a frequency-dependent equation for the conductivity of your dielectric. For more information about using equations, please refer to Equation Syntax.

Most common dielectrics have either a fairly constant loss tangent or conductivity as a function of frequency. Thus, it is normally not necessary to specify an equation for your dielectric loss. You can even enter both a loss tangent and a conductivity (or resistivity) for a dielectric and two values are combined to provide the total loss for your analysis. The following equation can be used to calculate the total effective tand used by em for this situation:

where, ω is the radian frequency (ω = 2πf, where f is frequency in hertz). Note that tanδ has both a frequency-dependent term and a frequency-independent term

The above equation for tanδ can also be expressed in terms of conductivity as follows:

Both equations are equivalent. Each describes how em uses the input dielectric parameters to compute loss in the dielectric material.

Note: If resistivity is input, instead of conductivity, the equation used is altered accordingly.

See Dielectric Layers page in the Circuit Settings dialog box for information on setting these parameters.