| Summary: | 碩士 === 國立交通大學 === 電信工程系所 === 92 === In this thesis, we propose a novel design method for multi-band antenna. We utilize the concept of λ/2 open-loop resonator used in microwave filter frequently, and combine this concept with the resonant antenna. This novel antenna adopts two different resonant types operating two different frequencies. One is the conventional inverted-L monopole for higher operating band, and the other is λ/2 open-loop resonator for lower operating band. As these two different resonant types coupling each other, this antenna only need one feed network to produce dual-band purpose. This antenna is fabricated on PCB board and total size is 13×10mm2. In this thesis, we also establish the equivalent circuit model for this dual-band antenna to verify how important the coupling strength affects this antenna. From experiment, the resultant bandwidth is suitable for 802.11a/b/g WLAN applications. The radiation pattern is close to omni-directional, and the largest average gain can achieve around 0dBi for each measured frequency.
Furthermore, we also verify the performance of this dual-band antenna is not affected seriously by the variation of FR4 manufacture parameter. Finally, we also utilize this novel dual-band antenna to design diversity antenna. In this diversity antenna, we use some simple barrier object occupying little size to decrease the coupling effect between two antennas.
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