A negative index metamaterial antenna for UWB microwave imaging applications

Abstract

In this article, a negative index metamaterial antenna ispresented for ultrawideband (UWB) microwave imaging applications.Four left-handed (LH) metamaterial (MTM unit cells are located alongone axis of the antenna as the radiating element. Each left-handed meta-material unit cell assembles a modified split-ring resonator with acapacitance-loaded strip to obtain a design architecture that at a timeshows both negative permittivity and negative permeability, whichassures the stable negative refractive index to raise the antenna per-formance for microwave imaging. The antenna structure of dimension16 3 21 3 1.6 mm3is printed on low dielectric FR4 material with aslotted ground plane and a microstrip feed. Measured reflection coeffi-cient illustrates that this antenna attains 114.5% bandwidth covering thefrequency band of 3.4–12.5 GHz for a voltage standing wave ratio lessthan 2 with a maximum gain 5.16 dBi at 10.15 GHz. There is a stable harmony between simulation and measured results and improved nearlyomnidirectional radiation characteristics within the operational fre-quency band. The stable surface current distribution, negative refractiveindex characteristic, considerable gain, and radiation property havemade this proposed negative index metamaterial antenna distinguishablefor UWB microwave imaging applications. Full Text Link: http://doi.org/10.1002/mop.29095