| Summary: | 碩士 === 義守大學 === 電子工程學系 === 101 === This thesis combines the metallic-disturbing technique and cylindrical microstrip structure to design dual-band antennas with the function of either for size reduction, double frequency separation or used at commercial band. These microstrip are designed with the metallic-disturbing structures include various geometries such as sector, notch or annular ring type.
For the characteristics of sector-type circular microstrip antenna, theoretical results show that the technique of metallic-disturbing can change the distribution of electric field in order to achieve two modes with single-beam radiations, design scheme is also verified. While the technique of metallic-disturbing is applied to those antennas with sector type, notch type or annular type, all of them can operate at dual bands. In addition, the advantages of antenna with size reduction and double frequency separation can increase the design flexibility as well. Moreover, after the adjustment of structure parameters of annular ring, this microstrip antenna can operate at GSM system. According to these four different designs, their various distribution of electric field by metallic-disturbing technique show the high freedom for antenna design.
As for the analysis method, this thesis employs the concepts of cavity model, half cavity skill and moment method to investigate basic characteristics of sector type microstrip antenna as an example. Complicated analysis procedure is simplified and the basic antenna parameters such as resonant frequencies and distribution of electric fields become easy to obtain. Meanwhile, those theoretical results also confirm design scheme. The result from simulation and experiment do not only verify the practice of metallic-disturbing technique but also increase the efficiency during design.
The four types of antennas in this thesis can operate with multiple functions by the employment of metallic-disturbing technique. Therefore, once the disturbing structures can vary the electric field more effectively, an antenna with more functions could be expected.
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