Practical finite difference time domain (FDTD) shielding analysis of thin coatings and shield bonding methods

Thin coatings such as indium tin oxide (ITO) or gold splatter on glass are often used on electronic display enclosures for shielding to allow compliance with radiated emissions standards while allowing optical transmission. The thin coatings are often bonded to the display enclosure to allow realization of the maximum shielding. The bonding is often accomplished by the use of a conductive gasket that mates with a busbar on one or more edges of the thin coating. Shielding effectiveness of the coating and gasket configuration is very difficult to predict using traditional shielding effectiveness equations. This paper shows how 3-dimensional (3D) finite difference time domain (FDTD) simulation and analysis are used to examine trends in shielding effectiveness with respect to gasket characteristics, thin coating characteristics (thickness and conductivity), and bonding methods. Practical simulation and model setup methods are presented. Results are provided for common configurations.