A review: Advancement in metamaterial based RF and microwave absorbers

Abstract

Microwave absorbers (MAs) are specially designed structures which dissipate an incident electromagnetic (EM) wave by converting it into thermal energy and thereby prevents reflection and/ or transmission. The MAs are extensively in demand due to their property to reduce the electromagnetic wave interference (EMI) and to enhance electromagnetic shielding (EMS). MAs are also used in potential military applications as a stealth technology to design stealth aircrafts, warships and army clothing etc. due to the reduction of radar cross section (RCS) of the defense equipment by the absorber coating. In this review work, study of metamaterial-based MAs, their characteristics viz. left-handed material property, permittivity and permeability have been discussed in detail. Metamaterials (MMs) or artificial materials that play a significant role in reducing the size and thickness of MAs depending upon the frequency of operation. In this work, theoretical background of MM-based absorbers detailing the effect of permittivity and permeability on absorber performance has also been discussed. Different applications of absorbers are elaborately covered in this paper. Furthermore, frequency selective surface (FSS) which is a two-dimensional array has the capability to reflect or transmit EM wave completely or partially depending upon the nature of FSS. Therefore, distinct categories of FSS-based absorbers are discussed according to the frequency of operation, bandwidth and material specification where the effect of different design parameters is also critically analyzed. The objective of this review paper is to provide an exhaustive study of the unique attributes of MAs having a diverse range of applications for frequencies ranging from microwave, terahertz upto optical frequency domain. This review paper is certainly a vital tool for researchers to accurately understand, explore and work on MA design and selection as per user defined specific frequency and applications.