可塑性四極化掃描天線之設計

Abstract

本論文著重可塑性平面式微帶線槽孔耦合四極化天線之設計。因為在通訊系統中極化掃描可以降低多重路徑效應造成之衰落損耗，並可以有效提升通道容量且提高雜訊比大大提升通訊系統的效能，故近年來已漸漸被重視。目前已有極化掃描的應用在各種不同之無線通訊系統中，例如:無線區域網路、無線射頻標籤辨識系統(RFID)、多埠輸入多埠輸出系統(MIMO)和手機通訊等等，更加印證了極化掃描在通訊系統中的重要性。但是目前天線設計大都為雙極化天線，如雙線性極化或雙圓形極化，亦或是單線性極化搭配單圓形極化之雙極化天線。極少數天線具有四極化掃描特性(雙線性和雙圓形極化)。本論文將提出三種不同之平面式四極化掃描微帶線槽孔耦合天線架構，並且利用PIN二極體來設計不同的饋入網路，藉著改變PIN二極體偏壓來改變天線的饋入網路結構，造成極化天線不同之極化狀態，以達到極化掃描之目的。因此，藉由巧妙之饋入網路設計即可達到四極化操作，以便達成單一天線可以提供雙線性極化以及雙圓形極化之極化掃描特性。

This thesis is devoted in design of the reconfigurable planner microstrip aperture coupled quadri-polarized antenna. Nowadays, the polarization diversity is more and more attracted in communication system. It is effective to counter the fading loss caused by multi-path effects and double the channel capacities. Also, polarization diversity increases the SNR and performance of the communication systems greatly. The polarization diversity is applied in WLAN、RFID and mobile communication that prove it is very important in communication systems. Majority of the polarized antennas own dual-polarization characteristics but few polarized antennas can provide four polarization senses. In this thesis, three planar reconfigurable quadri-polarization microstrip aperture-coupled patch antennas are proposed. They can switch the different polarization scenes by controlling the pin-diodes embedded in the feeding network.