Surface resistance of superconducting microwave passive devices

When a superconducting passive microwave device is hit by an electromagnetic wave from either the film side or the substrate side, it exhibits different surface resistances. In the former case the surface resistance is that of a bulk superconductor if the film is thick; while in the latter case it is higher than the value of the bulk superconductor under typical experimental parameters, depending on the material and thickness of the substrate.