Defect induced co-polarization broadband metamaterial absorber

Tran Sy Tuan,Nguyen Thi Quynh Hoa

doi:10.1063/1.5097198

Abstract

We propose a simple and new approach to design the broadband metamaterial absorber (MA) based on FR-4 substrate. The defected resonant patch of symmetry MA unit cell has been conceived to achieve the broadband absorbance. The simulated results demonstrate that the defected absorber structure exhibits the co-polarization broadband absorption response with absorptivity higher than 90% in the range of 4.0 - 6.0 GHz and the relative absorption bandwidth (RAB) of 40% for normal incidence. Furthermore, the defected structure can maintain the absorbance above 80% for oblique incidence up to 50° under both transverse electric (TE) and transverse magnetic (TM) polarizations. The compact structure (unit cell dimension of ∼λ/5.5 and thickness of ∼λ/20.8 with respect to the lower resonant frequency) and co-polarization broadband absorption with wide incident angle insensitivity of the absorber design based on defect make it suitable for defense system applications. Furthermore, this approach can be used to design co-polarization broadband absorbers in the terahertz, infrared and optical frequencies.

Highlights

Metamaterial absorber (MA) has drawn a lot of attention for various applications since a thin perfect microwave metamaterial absorber was developed by Landy et al in 2008.1–9 In particular, the controllable design of MA structure has been studied extensively in order to obtain a compact size, wide bandwidth with a wide-angle and polarization insensitivity, and suitable operating frequency band for practical applications
In order to enlarge the absorption of symmetry MA structure, the array of various different sizes of MA in the single layer has developed,10,14,15 this approach increases the period of unit cell significantly and it is difficult to obtain a wide bandwidth
We propose a simple and new approach to design of co-polarization broadband and wide-angle insensitive MA based on a single layer of metal - dielectric - metal configuration

Summary

Introduction

Metamaterial absorber (MA) has drawn a lot of attention for various applications since a thin perfect microwave metamaterial absorber was developed by Landy et al in 2008.1–9 In particular, the controllable design of MA structure has been studied extensively in order to obtain a compact size, wide bandwidth with a wide-angle and polarization insensitivity, and suitable operating frequency band for practical applications. The symmetry resonance structures such as circle, square, ring, and cross have developed for absorber design in various frequency ranges from microwaves to optical frequencies.. The symmetry resonance structures such as circle, square, ring, and cross have developed for absorber design in various frequency ranges from microwaves to optical frequencies.10–18 These absorber structures exhibit the narrow absorption band due to these resonant features. The using of an asymmetry structure with a sustained direction can broaden the absorption band due to the combination of adjacent resonant peaks which created by different sizes of resonant shape. the asymmetry MA structure has been attractively studied and applied in the defence systems that not require the polarization insensitivity such as radar cross section reduction (RSC), stealth technology, and EM interference (EMI) reduction. For example, Gong et al reported the design of sectional asymmetric structures which can manipulate the bandwidth with absorptivity larger than 90% is extended by about 2.8 times compared with the conventional square ring absorber.

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Results

Conclusion