Synthesis and Analysis of Metamaterial Structure for Microwave Frequency Applications

Abstract

produce uncertainty, therefore, most of the conventional extraction technique rely on relatively thin materials. In the thick materials, the ambiguity appears in different frequency points in several branches which produces phase error. Thus, it is essential to check the proper branch that minimizes the ambiguity and this remains under explored. This doctoral research aims to fill this gap in the scholarly literature by developing a unique extraction technique that will support reducing the ambiguity error and is able to provide accurate values for electromagnetic properties. To achieve this aim, the initial research concentrated on the Nicholsonross-weir (NRW) technique. The modified NRW technique is then applied to a long-length Drude material with known parameters for validation. Another extraction technique known as Kramers-Kronig (KK) technique is also investigated. This KK extraction technique is applied to the use of Cauchy residue integrals instead of using trapezoidal rule integration. Further investigations involved experimentation by using the proposed NRW extraction technique to provide empirical evidence, such as designing a periodic dual-star split ring Synthesis and analysis of metamaterial structure for microwave frequency applications iii resonator (DSSRR) and microwave absorber. DSSRR is an electromagnetic band gap (EBG) based metamaterial structure. The proposed DSSRR structure may be implemented with an equivalent transmission line structure. The advantage of the transmission line structure is that it realizes the artificial structure with minimum losses and produce wide bandwidth. The DSSRR structure is implemented on single unit cells and multiple unit cells. The proposed DSSRR structure delivers a wide-band performance from 7.5 GHz to 9.5 GHz and a maximum rejection up to 47 dB, which offer a sharp cut-off in the reject band. The dispersion diagram exhibits unusual characteristics in both balanced and unbalanced conditions. A microwave absorber was also developed. The proposed design offers three unique shapes without using any additional resistive sheets on top of the ground plane.The three unique shapes are octagonal ring, (OR), cross-wires (CWs), and cut-off circle (CC). The proposed shapes are insensitive to polarization angle, and can achieve perfect absorption. Further work involves the successful extraction of electromagnetic properties using the NRW technique. The numerical and experimental results agree with each other, which further confirms the metamaterial behaviour.iv Synthesis and analysis of metamaterial structure for microwave frequency applications

A Broadband Polarized Metamaterial Absorber Driven by Strong Insensitivity and Proximity Effects

“…Numerical and experimental results show excellent agreement and confirm the theory. The geometry of a single unit cell is shown in Figure 1 (a)-(b) along with its three different shapes: cross-wire, octagonal ring, and cut-off circle [14]. The key parameters are s = 3 mm, p = 12 mm, t = 0.75 mm, cross-wire width (cww) = 0.3 mm, octagonal ring width (orw) = 0.2 mm, cutoff circle radius (ccr) = 5 mm, l = 78 mm.…”