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Title:	Left-handed metamaterial for microwave shielding application
Authors:	Farhad Ashraf (P86161)
Supervisor:	Mohammad Tariqul Islam, Prof. Dr.
Keywords:	Metamaterials Electromagnetic waves Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	24-Nov-2018
Description:	Electromagnetic (EM) radiation is now one of the public concern that is encountered in microwave applications. The amount of electromagnetic radiation exposed from wireless devices and the consequences on human health has become a substantial research topic. Metamaterial, an artificial media with extraordinary electromagnetic properties, has drawn the interest of thousand researchers and continues to inspire. The artificially engineered structure has become a significant breakthrough to reduce the biological effect of the electromagnetic absorption towards the human body. This thesis emphasizes on development and characterization of microwave metamaterial due to their structural miniaturization, microwave circuitry and implementation on current technology. In this research, the design process of three different frequency bands, detailing the characterization of metamaterial and a plausible explanation for the phenomenon have been analyzed. The finite element method (FEM) based full wave simulator Computer Simulation Technology Microwave Studio has been used to design and analyze the scattering parameters of the structure. The characterization of the metamaterials has been extracted by the transmission-reflection method. The first design considered a modified split-ring resonator (MSRR) and a capacitive loaded strip (CLS) to achieve the left-handed property. The fabricated prototype is an inkjet-printed metamaterial using silver metallic nanoparticle ink, on a very low-cost flexible photo paper as a substrate material. A double negative region from 8.72 GHz to 10.91 GHz (bandwidth of 2.19 GHz) in the X-band microwave spectra has been found with an electrical dimension of 0.29λx0.29λx0.007λ, λ is the free space wavelength at center frequency. The second design is based on an elliptical split-ring resonator (ESRR) with a CLS in the middle to increase the electrical length and coupling effect. Transmission characteristics of FR-4 and Rogers RO3010 are investigated in a comparative manner for varying values of substrate parameters which are thickness, dielectric constant and dielectric loss tangent. It shows a double negative regime from 3.6 to 5.6 GHz (bandwidth of 2 GHz) for FR-4 and from 3.1 to 4.8 GHz (bandwidth of 1.7 GHz) for RO3010 in microwave frequency spectrum. In the third design, a meander line structure (MLS) technology is introduced by replacing the CLS to achieve size reduction, low profile and low absorption. It also has two double negative regimes one is from 2.46 to 3.31 GHz (bandwidth of 850 MHz) and another one is from 3.85 to 4 GHz (bandwidth of 150 MHz) while maintaining an effective medium ratio (EMR) of 12.86. The analysis demonstrates a 35.93 % reduction in the specific absorption rate (SAR) value at 2100 MHz. Experimental results confirm shielding effectiveness (SE) of the prototypes over a wide band with more than 20 dB measured attenuation. Using proposed left-handed microwave metamaterials as a shield, the human body can be protected from electromagnetic radiations and can also reduce the radio frequency (RF) signal interference of electronic devices, equipment and systems.,Master of Science,Certification of Master's/Doctoral Thesis" is not available"
Pages:	98
Call Number:	TK7871.15.M48F347 2018 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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