An update on the design and synthesis of compact absorber for EMC chamber applications

The paper describes and presents design parameters and methods for the synthesis of broadband “hybrid” absorbers using ferrite tiles and multilayered, carbon-loaded, dielectric materials. Measured data are compared with predicted values of reflectivity for prototype and production absorbers. Normalized site attenuation results are presented demonstrating improved performance for radiated emissions per ANSI C63.4. The original development effort [Ellam, 1994] included a survey of ferrite absorbers, design and construction of specialized test fixtures, computer modeling of basic and complex absorber structures, measurement of bulk dielectric parameters such (permittivity/permeability), examination of production and economic constraints, and measurement of new absorbers in EMC semi-anechoic chambers. The present follow-on paper is limited to a brief overview of the of previous survey results, new computer modeling of absorber structures and the design tradeoffs involved in the design of a broadband hybrid EMC absorber. Hybrid absorber designs ranging from 0.41 m to 1.5 m thick were investigated