Authors: Filippo Costa (1) Alireza Kazemzadeh (2) Simone Genovesi (1) Agostino Monorchio (1)
Source: FERMAT,Volume 13,Aricle,Jan-Feb,2016
Abstract: Frequency Selective Surfaces (FSSs) are bidimensional arrays of particles arranged in a periodic manner. These surfaces can be lossless or lossy, depending on the manufacturing process. They can be fabricated by using metallic or controlled-resistance surface deposition. Lossy surfaces can be also obtained through the integration of lumped components on a metallic surface. The use of FSSs has fostered new research lines in the design of electromagnetic absorbing surfaces, bringing improvements both in terms of bandwidth/thickness ratio maximization and in terms of customizability of the absorbing bandwidth (narrowband, multi-band, wideband, ultra-wideband) for specific applications. Artificial impedance surfaces (or HighImpedance Surfaces, - HIS) are thin resonant cavities synthesized by printing a periodic frequency selective surface on the top of a grounded dielectric slab. By proper tailoring of the geometrical and electrical properties of the FSS as well as the substrate, several electrically thin absorbing designs can be obtained. Ultra-narrowband absorbers with extremely stable angular behavior, often addressed as metamaterial absorbers, can be realized by exploiting only dielectric losses of commercial substrates. Narrowband, wideband and ultra-wideband configurations are instead implemented by also resorting to ohmic losses in a non-conductive FSS. A thorough review of the available absorbers will be presented together with multi-band and tunable design techniques. Manufacturing processes and practical examples will be also addressed, and the most interesting fields of application of the presented structures will be described.
Index Terms: Artificial Magnetic Conductor (AMC), Artificial Impedance Surface (AIS), Electromagnetic Absorbers, Frequency Selective Surface (FSS), High Impedance Surfaces (HIS), Metamaterial.
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Electromagnetic Absorbers Based on Frequency Selective Surfaces