Low-Frequency Shielding Effectiveness of Conductive Glass

The shielding effectiveness of conductive glass at low and intermediate frequencies (100 kc to 1,000 Mc) was investigated. A mathematical model was used to describe the absorption and reflection. This model is based on a film applied to the glass substrate which represents a barrier with finite thickness and relative conductivity. Experimental data agreed well with theoretical calculations. Coated glass exhibits a permeability similar to that of free space, so that low-impedance attenuation is limited to the conductivity of the film. The analysis is primarily concerned with high-impedance, near-field incident waves. Transmission in the visible spectrum was also determined for several 4-by 4-inch conductive glass samples which vary in surface resistance from 9 to 125 ohms/square. Larger samples (8 by 3 feet) of conductive glass were also investigated.