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https://ptsldigital.ukm.my/jspui/handle/123456789/519675| Title: | Design and analysis of compact planar antennas for ultra-wideband applications |
| Authors: | Rezaul Azim (P49160) |
| Supervisor: | Mohammad Tariqul Islam, Assoc. Prof. Dr. |
| Keywords: | Ultra-wideband devices Antennas (Electronics) Ultra-wideband antennas Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia |
| Issue Date: | 4-Jun-2012 |
| Description: | Ultra-wideband (UWB) technology has been expanding as a promising wireless communication technology and wireless terminals for upcoming applications necessary to provide different services. This increasing demand speeds up the necessity of antennas capable of covering ultra-wide and multiple bandwidths for numerous applications. The design of UWB antenna is quite challenging compared to its narrowband counterpart. A suitable antenna must have broad impedance bandwidth to cover the entire UWB with satisfactory gain, stable radiation patterns and good time domain behavior. The conventional 3D monopole antennas are not suitable for embedding in portable devices due to their large perpendicular ground plane which poses a challenge for designing compact UWB antennas. This thesis focuses on the design, development and modeling of antennas for UWB applications that achieve a physically compact, planar profile, sufficient bandwidth, stable radiation patterns and good time domain behavior. Extensive investigations are conducted on two sets of antennas. The first set of planar antennas focuses on rectangular, circular disc and tapered shape slot antennas with fractional bandwidth more than 100% to cover the entire UWB frequency range. The modification of ground plane reduces the ground plane dependency and increases the impedance bandwidth while the addition of different types of slots enhances the bandwidth further. The second set of antennas is proposed for band notched applications. Resonating elements such as slots and parasitic slits are used to the proposed antennas to create rejection bands that are occupied by WiMAX and WLAN to avoid interference between UWB and these narrow bands. The antenna performances were analyzed by electromagnetic computation technique based on method of moments to understand the antenna operations. Experimental performances of the fabricated prototypes were measured in both frequency and time domain. It has been observed that all antennas achieves more than 115% impedance bandwidth to cover the frequency spectrum of 3.1-10.6 GHz, a satisfactory gain of more than 5.4 dBi, a radiation efficiency of more than 88%, exhibit stable omni-directional radiation patterns with low cross polarization and good time domain behavior which make them suitable for being used in different UWB applications. Additionally, band notch elements successfully notched the narrow bands of 3.3 - 3.7 GHz and 5.1 - 5.9 GHz in UWB frequency band to avert the interference. Moreover, a physical augmentation with tuning method is proposed for extracting the equivalent circuit for UWB.,Certification of Master's / Doctoral Thesis" is not available |
| Pages: | 185 |
| Call Number: | TK7871.67.U45A998 2012 3 tesis |
| Publisher: | UKM, Bangi |
| Appears in Collections: | Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina |
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