| Summary: | 碩士 === 國立臺灣大學 === 應用力學研究所 === 94 === Mcrostrip patch antenna is a low-profile robust planar structure which can achieve a wide range of radiation patterns. However, patch-antenna designs have some limitations such as restricted bandwidth of operation, low gain, and a potential decrease in radiation efficiency, as a result of surface-wave losses.
In order to minimize the surface-wave effects, a photonic-band gap (PBG) substrate is proposed in recently years. The PBG structure antenna shows significantly reduced levels of the surface wave modes compared to conventional patch antennas, and thus improves the gain and far-field radiation pattern and efficiency. In order to meet these requirements, photonic crystal slabs and woodpile structure in this thesis are applied and integrated with antenna. Simultaneously, the simulations of 3D photonic crystals band gap are also represented, in order to find out the corresponding optimal parameters of slabs and woodpile structure with respect to patch antenna.
Another point is that the suppression of surface wave in microstrip antennas. In addition, simulation of reducing surface wave propagation in a rectangular microstrip patch antenna with and without PBG is presented. Therefore, the proposed analytical models are suitable for active integrated antennas and applied to improve performance of a broadband circularly polarized patch antenna.
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