| Summary: | 碩士 === 國立臺灣大學 === 電信工程學研究所 === 94 === In this thesis, we have designed the monopole antenna over frequencies 3.1-10.6GHz for UWB applications and the dual-band antenna over the interested spectrum 2.4-2.5GHz and 5-6 GHz for WLAN applications such as IEEE 802.11a/b/g using coplanar waveguide as the feeding transmission line. The antenna gain is about 2dBi to 4dBi which corresponds to a good gain flatness characteristic within the UWB spectrum. The total antenna size is about 30mm x 30mm, which is small compared to some wideband slot antenna designs. A parameter study is given to understand the UWB antenna behavior. In order to block the present WLAN bands, which are 5.15 to 5.35 GHz for HYPERALN/2 and 5.725 to 5.825 GHz for IEEE 802.11a, a slip is inserted in the designed UWB antenna to block the original resonance at about 5.5 GHz. The notched method not only rejects the band of 5 – 6 GHz, but also produces a higher gain in 10 GHz compared to the normal case. This novel antenna can be used in the very wideband application such as UWB system.
In addition, we propose a new method to design the slot dipole antenna in order to get more bandwidth and compact size. We use this method to design a WLAN antenna works on 5-6 GHz in application of IEEE 802.11a with the dimensions of 15mm × 16mm for IEEE 802.11b/g and a dual band antenna works on 2.4-2.5GHz and 5.15-5.85GHz in application of IEEE 802.11a/b/g with the dimensions of 2mm × 2.2mm.
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