- 學位論文
極化與波束可調變之自適應天線系統
A Polarization- and Pattern-Reconfigurable Self-Adaptive Antenna System
摘要
本論文提出可分析外界接收訊號，極化自我調變且最佳化波束導向之自適應天線系統。此天線系統可以適應在各種不同的傳輸環境，並達到最佳的表現。 吾人首先簡介電磁領域中常見的最佳化方法，並分別介紹基因演算法與貪婪演算法，以及其應用於吾人所提出之天線系統之方法。 接著，吾人使用了極化可調之U型槽孔貼片天線做為系統中之天線陣列裡的單一元件。此天線單元藉由兩個射頻二極體與外接之直流偏壓電路，改變天線之電器結構，以切換天線之極化。此天線可以在線性極化、左圓極化與右圓極化之間任意切換。 最後，吾人將資料擷取卡、最佳化演算法、天線陣列與其他元件整合成一極化、波束皆可自我調變之自適應天線陣列。此天線系統可以分析來波之方向與極化，自動調整天線極化，並使用最佳化演算法，將波束方向調整至來波方向，以適應任何傳輸環境的改變。所有的模擬以及量測資料皆呈現於此論文中。
並列摘要
In this thesis, a self-adaptive antenna system is presented. This Antenna system analyzes the incoming signal, changes its polarization state, and optimizes the main beam direction by the implementation of optimization algorithms. This antenna system can automatically adapt itself to various communication environments. At the beginning, the common optimization algorithms in electromagnetic application are introduced. The optimization algorithms and the methods to apply them on the presented antenna system are also described. Furthermore, a polarization-reconfigurable U-slot patch antenna is utilized for the single element of phased arrays in the antenna system. This U-slot patch antenna is able to change its polarization by two pin diodes. With different dc biasing, pin diodes can adjust the electronic structure of U-slot patch antenna, which make the polarization be tunable. The antenna enables switching between linear polarization (LP), left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP). Finally, the data acquisition card, optimization algorithms, U-slot patch arrays and other components were integrated into a polarization- and pattern-reconfigurable self-adaptive antenna system. This antenna system is able to identify the polarization and direction of incoming signal. After that, the antenna system by itself adjusts the U-slot patch array to corresponding polarization and steers main beam toward the direction of incoming signal. All the simulated and measured results are presented.