A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

Abstract

A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm3, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4–12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.

High Gain Slotted Waveguide Antenna Based on Beam Focusing Using Electrically Split Ring Resonator Metasurface Employing Negative Refractive Index Medium

“…Unfortunately, the aforementioned approaches suffer from large sizes, design methodology, complex feeding network and fabrication processes, particularly in the high frequencies. As Pendry investigated the first negative refractive index perfect lens (i.e., double negative MTMs with simultaneously negative permittivity, permeability and negative index of refraction) in 2000 [17], it is possible to design a compact size and high directive antennas [18,19]. Furthermore, metamaterial structures composed of 3-D metal grid superstrates have been used to improve the directivity of the antennas [20,21].…”

A Miniaturization of Microstrip Antenna Using Negative Permitivity Metamaterial Based on CSRR-Loaded Groundfor Wlan Applications

“…However, these approaches can make the low bandwidth, efficiency, and gain of antenna [8]. Recently, using metamaterial (MTM) in antenna design has been developed for improving antenna parameters and miniaturizing antenna size [9,10]. Nevertheless, the approach method is required the sophisticated structures which can be fabricated costly and time consuming.…”

“…Nevertheless, the approach method is required the sophisticated structures which can be fabricated costly and time consuming. For example, Islam et al reported that a negative index MTM created by combining a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) which installed on the radiating patch to obtain the antenna design architecture that simultaneously exhibits both enhanced antenna performance and reduced the antenna size [9]. It was also reported the using of 3D isotropic µ-negative (MNG) MTM loaded on a microstrip circular patch antenna to reduce size and obtain good performance [10].More recently, the use of multi-CSRR resonances etches on ground plane of microstrip antenna for size reduction and gain enhancement [11 -13].…”

Dual-band polarization angle independent 90° polarization rotator using chiral metamaterial

“…Metamaterials are a series of composite materials that can exhibit some special properties. Depend on these properties, we can obtain many applications [1,10,11]. Chiral metamaterials (CMMs) [1,12], which are constructed from artificial sub-wavelength metallic cells, have recently been reported to exhibit strong optical activity.…”