A Wideband Lateral Excited Metamaterial Unit Cell with High Refractive Index

Abstract

Metamaterial unit cell-based lens antennas have been widely investigated due to their outstanding ability of controlling electromagnetic wave [1] . On the basis of different metamaterial unit cell design, negative-, low/zero-, and gradient-refractive index lens antennas have been developed. In general, the metamaterial unit cell with high refractive index and wideband is preferred in such designs to improve the lens’ performance. Traditionally, the lenses are usually excited by normal or oblique incident waves. For some special applications, such as end-fire lens antenna [2] and planar antenna [3] , metamaterial lenses usually located inside the radiation aperture or the unit cell is printed on the substrate, making the lateral excited lens is more applicable. Besides, the lateral excitation scheme avoids the limitation of choosing the height of commercial substrate, especially for the lenses composed of core layer and corresponding impedance layer. Therefore, a wideband lateral excited metamaterial unit cell is proposed and its effective refractive index is investigated in this contribution.