Surface Roughness Calculation for Impedance Boundary

The surface roughness is measured as the RMS deviation of the conductor surface from a plane. Surface roughness increases conduction losses. HFSS calculates surface roughness by modifying the conductivity as follows:

(1)

where

sis the material's conductivity.

(2)

where, further:

• h is the surface roughness.
• s is the skin depth.