Design and analysis of double incidence metamaterials composed of mushroom-shaped structure

Abstract

An ultra-wide band metamaterial may be achieved via the design of some structures. A metamaterial unit supporting two-dimensional (2D) incident electromagnetic (EM) wave is proposed based on the mushroom type-structures, which has an ultra-wide band with seamlessly combined band of right-handed and left-handed pass-bands. This unit is designed by setting two reverse symmetrical mushroom-shaped strips on each side of the dielectric substrate respectively, and the electric resonance and the magnetic resonance could be excited simultaneously. With CST software, the right-handed and left-handed properties are analyzed and verified by means of spectrum analysis, effective parameters of permittivity, permeability and index of refraction extracted from S parameters, and equivalent magnetic resonance circuits. The results show that the structure can present left-handed properties with 1 GHz left-handed pass-band in X waveband, either EM wave is incident in the direction perpendicular or parallel to the plane of the substrate. When the EM wave is incident in the direction perpendicular to the substrate, the right-handed and the left-handed pass-bands appear at 7.2 GHz9.3 GHz and 9.3 GHz11 GHz respectively; while when the EM wave is incident in the direction parallel to the substrate, the right-handed and the left-handed pass-bands appear at 7.0 GH9.0 GHz and 9.0 GHz10 GHz respectively. It also shows that the zero indexes of refraction occur at 9.3 GHz and 9.0 GHz in the tow instances above. So that a plus-zero-negative metamaterial is constructed and a 2D incident balanced-structure with an ultra-wide band of 3 GHz is achieved.