Technical Notes > The HFSS Solution Process > Solution Types > Eigenmode Solutions               

Calculating the Quality Factor

Q is the unloaded quality factor, and is a measure of how much energy is lost in the structure due to lossy materials. Because ports and other sources are restricted for Eigenmode solutions, the Q calculated does not include losses due to those sources.

HFSS uses the following equation to calculate the approximate quality factor:

(1)

The Fields Calculator can also be used to calculate Q. In general, the equation for Q is

(2)

where:

• U is the total energy stored in the cavity.

• P is the power lost, from resistive losses, for example.