Electromagnetic absorber design challenges

Design of low cost, light-weight, and flexible electromagnetic (EM) shielding structures, required for EM interference (EMI) mitigation is a complex problem. The complexity increases in manifolds since the EMIs, occurring over a wide range of frequencies, are of unknown polarization and may appear from an unknown direction. This article aims to address all the challenges and complexity prevalent in the design of shielding structures with the help of several self-explanatory diagrams. These diagrams present a concise yet clear explanation of EMI environment along with the review of the most popular and recent techniques used in the design and development of EM absorber (EMA) based shielding solutions. An attempt has been made to justify the need for thin and economical microwave absorbers for achieving good absorption characteristics over a wide range of frequencies within a specified band of EM spectrum. The absorbers satisfying all the existing constraints would be capable of suppressing EMIs from unknown EM radiators efficiently to the lowest possible level.