Analysis and design of transparent conductive coatings and filters

Abstract

Four types of transparent electrically conductive filters commonly used for a variety of applications are (1) a free-standing conducting inductive mesh, (2) a substrate coated with a conducting inductive mesh, (3) a conducting substrate, and (4) a substrate coated with a continuous conducting coating. Each can be designed to provide high visible, near infrared, and/or far infrared transmittance and high radio frequency (rf) and/or microwave attenuation. Theoretical models developed at Itek to predict the optical, rf, and electrical properties of each type of filter as a function of conductivity, relaxation time, electronic mobility, thickness, mesh period, and mesh line width are described. The temperature and angle of incidence dependence are also discussed. Simple expressions for predicting the performance of these four types of filters at both optical and rf frequencies provide both insight and useful starting designs.