| Summary: | 碩士 === 國立宜蘭大學 === 電子工程學系碩士班 === 96 === In this thesis, various planar slot antennas fed by CPW are proposed for UWB communication-system applications. First, an elliptical slot antenna with a circular stub fed by CPW is presented and discussed why it has ultra-wide bandwidth based on multiple resonance concept. The antenna is fabricated and experimental results show that its impedance bandwidth can cover frequencies from 3.1 to 10.6GHz, which meets system requirements. The radiation pattern also confirms its omni-directional pattern features, which is suitable for portable device or laptop computer application.
Then, a band-notched elliptical slot antenna is proposed to overcome interference with some already existing standards such as the IEEE802.11a and HyperLan/2A systems. This planar slot antenna using open-end slits on the tuning stub or a pair of parasitic strips in the aperture is studied and designed to reject this particular sub-band within 5-6GHz. Measured results show that this antenna not only retains ultra-wide bandwidth but also has band-rejection capability. Also, its radiation pattern still preserved omni-directional feature which meets our system requirements.
Finally, a compact and novel folded slot antenna, which its size is shrunken to a half of the original curved-shape structure, is proposed for practical UWB applications. From experimental results, it is found that it still preserved UWB characteristics although its radiation pattern seems not perfect for ultra-wideband transmission.
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