Analysis and Comparison of Plane Wave Shielding Effectiveness Decompositions

Plane wave shielding effectiveness is frequently expressed as the sum of three terms called absorption loss, reflection loss, and a multiple reflections term. This well-known decomposition was introduced by Schelkunoff and provides an intuitive way of relating material properties to the overall shielding effectiveness. This letter derives equations relating the Schelkunoff decomposition terms to the reflectance/absorptance of good conductors. Additionally, the relationship between the Schelkunoff decomposition and another decomposition, called the mismatch decomposition in this letter, is analyzed. The mismatch decomposition consists of two loss terms closely related to reflectance/absorptance that are readily obtained from measurements.