三維光子晶體厚板及層堆結構於微帶平板天線之改善設計

Abstract

微帶平面天線的好處在於能以低姿態卻又實用的平面結構得到高範圍的輻射場型，但是由於在天線結構上有表面波的損失，使得在平面天線上的設計有許多缺點，像是頻寬的受限、低增益，以及低輻射效率。 爲了改善平面天線，降低表面波，光子晶體在最近幾年被提議應用在平面天線的介質中。加上光子晶體的平面天線會比未加上光子晶體的天線更有效的降低表面波，並因此可進一步增加輻射場型以及增益。本論文主要是應用三維光子晶體厚板以及層堆結構在平面天線上，並爲了設計理想的光子晶體，利用套裝軟體模擬能帶，在一定的平面天線工作頻率下，配合完全能帶將三維光子晶體的尺寸大小最佳化，以結合平面天線。 另外，藉由套裝軟體的模擬呈現在加了光子晶體的天線之表面波，與未結合光子晶體的天線做比較，因此，可得到最好的輻射場型與效率。

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.