A study of the application of defected ground structure on the performance and characteristics of antenna system

• Main Authors: Chun-Hui Wu, 吳俊輝
• Other Authors: Kong-Kau Tiong
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/29350179779581676356

碩士 === 國立臺灣海洋大學 === 電機工程學系 === 94 === In this thesis, the application of defected ground structure on T-shaped monopole antenna and rectangular planar invert-F antenna were presented. The printed monopole antenna and PIFA are antenna of reduced size. The size reduction is a result of the reduced resonant wavelength which is a quarter of the conventional rectangular microstrip patch antenna. Therefore these two antennas have been widely implement and more attractive physical appearance in mobile terminals and WLAN applications for their small size. A pair of DGS in the ground plane was etched to modify the characteristics of the fed line such as line capacitance and inductance. The DGS under the microstrip transmission line can be modeled as L-C network to match the input impedance of the T-shaped monopole antenna for the enhancement of the antenna bandwidth. On the other hand, the DGS also serves as low pass filter (LPF) and can be used to suppress harmonics. The proposed monopole antenna demonstrated excellent performance for the bandwidth enhancement and harmonic suppression. The enhancement of the bandwidth is about 2.5 times over that of a T-shaped monopole antenna without the DGS. The frequency range is from 1.7GHz to 2.52GHz and can be applied to mobile communication system (DCS1800, PCS1900, WCDMA) and Wireless Local Area Network (WLAN). The resonant frequency of the planar inverted-F antenna has a relationship between current path and size of the radiation element, the lower resonant frequency depends on longer current path. The current path include the radiation element of antenna and ground plane, We have proposed using ground plane with H shaped slot for planar inverted-F antenna to extend the current path of the ground plane for size reduction. In this work, we have observed that the PIFA with shorting pin or shorting strip with the H shaped slot etched in the ground plane performed equally well in achieving the propose of size reduction.