Modeling of a Negative Refractive Index Metamaterial Unit-Cell and Array for Aircraft Surveillance Applications

Abstract

In this paper, a unique negative refractive index-metamaterial (NRI-MTM) structure is proposed for traffic alert and collision avoidance system (TCAS) for aircraft application. The NRI-MTM unit-cell structure is a combination of square and circular split ring structures. The proposed square and circular split ring metamaterial (SCM) is designed on the top of a 1.6 mm thick FR-4 substrate, with a single circular split ring on the bottom of the substrate. The total dimension of the SCM unit-cell is 23 × 23mm 2 (0.08𝜆 × 0.08 𝜆), resonating at 1.06 GHz. This unit-cell is further used to create a 5×4 array structure with a dimension of 130 × 111mm 2 (0.46 𝜆 × 0.4 𝜆). A High-Frequency Structure Simulator (HFSS) is used to assess the electromagnetic properties of the proposed structures. Furthermore, in order to analyse the double negative (DNG) behaviour of the designed SCM structure, the unit-cell is rotated from 0 to 360 degrees with a step of 60 degrees along the azimuthal plane. On doing so, it is observed that, the proposed SCM structures, including unit-cell and array structures, exhibit DNG and NRI properties over the frequency band of 0.5 to 1.2 GHz, thus making it optimum for aircraft surveillance application. The SCM unit-cell and 5 × 4 SCM array structure were fabricated, and the measured results are in well agreement with the simulated results. Further, the array structure is used as a superstrate on the patch antenna to analyze the impact of the MTM on the antenna performance. In comparison to the antenna without the MTM structure, the 5 × 4 SCM array loaded antenna has a gain improvement of 2.8dB and a bandwidth enhancement of 31.5MHz.

Design and Experimental Study of a Coupled U and L-Shape Negative Index Metamaterial for Aircraft Navigation Applications

“…𝜇 𝑒𝑓𝑓 = 𝑛 𝑒𝑓𝑓 . 𝑧 𝑒𝑓𝑓 (10) The parameters such as 𝑧, 𝑛, 𝜀, and 𝜇 for the proposed MTM structure are obtained by substituting the real and imaginary values of simulated 𝑆 11 and 𝑆 21 in the aforementioned formulas.…”

“…A coupled square and circular MTM structure with DNG property is proposed for ACAS applications in [9]. The structure is constructed on a FR4 substrate, and the compactness of the structure is explained using an EMR analysis.…”

“…In this work, the MTM cell is expanded to a 5 × 4 array and used as a superstrate to enhance the overall gain of the ACAS antenna. A bi-layer, inverted C-shape DNG MTM structure is proposed for ACAS applications to improve the overall antenna performance [10]. The proposed design is simulated on 1.6𝑚𝑚 thick FR-4 substrate with an overall dimension of 0.078𝜆 × 0.078𝜆 (𝑓 0 = 1.06𝐺𝐻𝑧).…”

Analytic Continuation, Phase Unwrapping, and Retrieval of the Refractive Index of Metamaterials from S-Parameters

“…Based on the above, if γ is the copy on S(L) of the path γ(t) lying in Ċ, we have from (11) that between the values taken by L(•) at z ′ ∈ γ(t) and the values assumed by L at z ∈ γ, the following relation must hold [23]:…”

“…In the last decade, researchers have shown great interest in developing particular three-dimensional artificial materials, usually made up of a lattice of metallic resonant inclusions arranged in a dielectric host medium called metamaterials (MMs), given obtaining devices endowed with exceptional operating performances [4]. To characterize MMs, the so-called heuristic homogenization approach, developed for the first time in [5,6], is the procedure most commonly employed by practitioners and researchers in the field [7][8][9][10][11][12][13][14]. In this peculiar framework, it is assumed that an MM, within its operating frequency range, can be considered analogous to a homogeneous medium, called the effective medium, for which the electromagnetic properties are described by an effective electric permittivity ϵ e f f and magnetic permeability µ e f f [5,6].…”