Design and Analysis of an Ultrawideband Multilayered Electromagnetic Absorber Using a Carbonyl Iron Magnetic Substrate and a Planar Periodic Conductive Structure for mmWave Applications

This article introduces a novel ultrawideband multilayer electromagnetic (EM) absorber for mmWave applications. The magnetic substrate of the absorber was constructed using a CIP/epoxy composite, which exhibits remarkable permeability up to approximately 20 GHz. The study examined a periodic square patch structure fabricated using an innovative lithography method, which serves as a capacitance layer and was analyzed using an equivalent circuit model. The newly derived analysis and design equation for the periodic structure showed high accuracy across a wide frequency range. The experimental measurements validated the efficacy of the proposed absorber, showing a 90% absorption bandwidth ratio of 1:3.95 from 11 to 43.5 GHz while maintaining a thickness of 1.7 mm (0.154λ ₀), whereλ ₀is defined as the center frequency in the operation frequency band.