Smith Chart-Based RAS Design

Abstract

Specifically the EM absorbers are in demand for the frequency range 1-40 GHz, because of their requirement in electromagnetic interference (EMI) shielding and countermeasure to radar detection. In defence sector, stealth technology demands such EM absorbers towards radar cross section (RCS) reduction.Total absorption of impinging electromagnetic (EM) wave requires the suppression of all propagation phenomena, viz. reflection, transmission, and scattering. The absorber can be a dielectric material or dielectric combined with metal plates placed at different intervals. The EM absorption is not difficult to achieve by increasing the volume of the absorber material and shaping its geometry, provided there is no limitation of space and weight. However practically, the space on airborne platforms is so limited that the designer has to consider various design factors, such as weight, thickness, absorptivity, environmental resistance, mechanical strength etc. This brief presents a detailed analytical formulation, step-by-step design procedure for EM design of Radar Absorbing Structures (RAS). Both the equivalent circuit model and Smith chart approach are discussed with illustrations. It provides the reader a clear understanding of the steps involved in designing multilayered RAS as per the desired specifications. This book will be helpful for beginners, academicians, and R&D engineers working in the field of RAS design and development.