Eur. Phys. J. B (2014) 87: 98
https://doi.org/10.1140/epjb/e2014-41072-y

Regular Article

A broadband, polarisation-insensitive and wide-angle coplanar terahertz metamaterial absorber

School of physics and Microelectronic and Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, Hunan University, Changsha 410082, P.R. China

^a e-mail: llwang@hnu.edu.cn

Received: 11 December 2013
Received in final form: 4 March 2014
Published online: 23 April 2014

Abstract

Broadband terahertz metamaterial absorbers have attracted considerable attention due to their significant potential for practical applications. These absorbers are usually stacked in several differently shaped or sized subunits to form a unit cell, making their fabrication quite troublesome. A simple design for broadband metamaterial absorbers is therefore urgently needed. Herein, we propose a coplanar broadband and polarisation-insensitive perfect absorber formed by two patterned square metallic rings with a dielectric layer on top of a metallic ground plane. The full width at half maximum (FWHM) of the device can be up to 42% (with respect to the central frequency), which is 2 times greater than that of a single-layered structure. This property is retained well for a very wide range of incident angles. The two patterned square rings resonating at different but similar frequencies leads to the broadband absorption. Moreover, a hybridised resonance model is proposed to analyse the origin of the resonance bandwidth. The results of this metamaterial absorber design appear to be very promising for solar cell, detection and imaging applications.