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https://ptsldigital.ukm.my/jspui/handle/123456789/487243Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Mohammad Tariqul Islam, Prof. Dr | |
| dc.contributor.author | Md. Moniruzzaman (P99997) | |
| dc.date.accessioned | 2023-10-11T02:31:06Z | - |
| dc.date.available | 2023-10-11T02:31:06Z | - |
| dc.date.issued | 2022-08-26 | |
| dc.identifier.other | ukmvital:130954 | |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/487243 | - |
| dc.description | Metamaterials (MTM) are artificial periodic structures with dimensions much smaller than the wavelength of incident waves and exhibit some extraordinary properties. MTM is utilized for various applications such as superlens, antenna gain and directionality enhancement, sensors, absorbers, radar cross section reduction, electromagnetic cloaking, and electromagnetic shielding. Most of the MTM unit cell found in the literature are not compact in dimension and exhibits harmonic distortion in an array configuration for wireless communication. Moreover, MTM with multifunctional capabilities, application frequency targeted design, and provision of easy frequency tunability is not also well practised for wireless communication systems. The objective of this research is to develop metamaterial structures considering these factors and analyze the performance of wireless communication systems. All these MTMs are designed using the 3D simulation tool CST microwave studio, whereas circuit simulation is performed in Advanced Design System to understand the resonance phenomena of the MTM. The performance measurement of the MTM is accomplished by using a vector network analyzer (VNA). MTM with antenna performance is observed using VNA for reflection coefficient (S11), whereas for gain and radiation pattern observation, Satimo near field measurement system is used. A metamaterial is developed that is symmetric about the vertical axis and provides transmission coefficient (S21) resonances at 2.38 GHz, 4.24 GHz, 5.98 GHz, 9.55 GHz, 12.1 GHz and 14.34 GHz with an effective medium ratio of 15.75. This metamaterial when used as a superstrate of a multiband antenna provides a maximum gain enhancement of 73%. Moreover, when the copper backplane is used same MTM acts as a good absorber exhibiting 99.6%, 95%, 78.3%, 99.9%, and 92% absorption at 3.98 GHz, 5.5 GHz, 8.48 GHz, 11.73 GHz and 13.47 GHz, respectively. Another negative permittivity metamaterial has been developed which is symmetrical about two perpendicular axes and it exhibits S21 resonances at 2.78 GHz, 7.7 GHz and 10.16 GHz with near-zero refractive index properties. The MTM provides 95% gain enhancement of an antenna when incorporated as a superstrate. In addition to this, another multiband mirror symmetric resonator based MTM is developed that has the design flexibility to adjust the resonances by using tuning metallic stubs. This MTM exhibits negative permittivity with near-zero permeability and refractive index. An MTM absorber has been developed that can be used to absorb incident waves of Wi-Fi frequencies. Tuning metallic stubs attached to the two rings of the resonator gives the flexibility to adjust peak absorption frequencies at 2.4 GHz and 5 GHz with the peak absorption of 99.20% and 99.9%, respectively. Moreover, MTMs, antennas, and MTM absorber performances are validated through measurement and good agreement is perceived between simulation and measurement. All these unique metamaterials can be effectively utilized for various applications in wireless communication systems.,Ph.D | |
| dc.language.iso | eng | |
| dc.publisher | UKM, Bangi | |
| dc.relation | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina | |
| dc.rights | UKM | |
| dc.subject | Universiti Kebangsaan Malaysia -- Dissertation | |
| dc.subject | Dissertations, Academic -- Malaysia | |
| dc.subject | Metamaterial structures | |
| dc.subject | Wireless communication systems | |
| dc.title | Analysis of metamaterial structures for wireless communication systems | |
| dc.type | Theses | |
| dc.format.pages | 179 | |
| Appears in Collections: | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_130954+Source01+Source010.PDF Restricted Access | 1.2 MB | Adobe PDF |  View/Open |
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