%0 Journal Article
%T Multiband Negative Permittivity Metamaterials and Absorbers
%A Yiran Tian
%A Guangjun Wen
%A Yongjun Huang
%J Advances in OptoElectronics
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/269170
%X Design and characteristics of multiband negative permittivity metamaterial and its absorber configuration are presented in this paper. The proposed multiband metamaterial is composed of a novel multibranch resonator which can possess four electric resonance frequencies. It is shown that, by controlling the length of the main branches of such resonator, the resonant frequencies and corresponding absorbing bands of metamaterial absorber can be shifted in a large frequency band. 1. Introduction Metamaterials, defined as artificial structures not found in nature, possess interesting properties, for example, negative refraction, perfect image, backward-wave radiation, reversals of both Doppler shift and Cherenkov radiation, and so forth [1每4]. It has recently shown that metamaterials can be used in various areas including microwave and optical components, absorbers, invisible cloaks, and so forth [5每9]. Due to these exciting properties and applications of metamaterials, in the past decade, various types of metamaterial configurations have been reported, operating at very wide frequency spectra ranged from microwave, THz, and even optical frequencies [10每13]. Quite recently, dual-band, multiband, and even band tunable metamaterials with single negative permeability or permittivity and double negative properties have been reported to enhance the operating frequency bands [14每19]. Also, the band-enhanced metamaterial absorbers were designed as well by using multiband electric resonators [20每23]. The mentioned band enhanced techniques for metamaterials and absorbers, however, restricted from their complex configurations and difficult controlling abilities. On another hand, in our previous research results [7], we have experimentally and numerically demonstrated a snowflake-shaped metamaterial absorber and obtained a well agreement between the measured and simulated results. The snowflake-shaped metamaterial resonator was composed of equal three main branches and six side branches. However, we found that it could achieve multiresonance frequencies when the main branches were not equal. In this paper, we firstly propose a simple design of negative permittivity metamaterial by using a multibranch resonator which can possess four electric resonance frequencies. The transmission and reflection characteristics are firstly investigated and then the effective electromagnetic parameters retrieved from the -parameters are determined. The tuning effects of the four operating frequencies by altering the main branches are discussed. Due to the fact that most of the single
%U http://www.hindawi.com/journals/aoe/2013/269170/