數種新型多天線系統分析方法

Abstract

在本論文中，我們研究了兩組評估多天線系統效能的電磁分析。第一項是輻射效率(Radiation Efficiency)的綜合分析，第二項是新型天線空間相關係數(Antenna Spatial Correlation)的計算方法。論文中所有的個案討論都將以偶極天線做分析基準。

首先，我們綜合分析了一個全主動反射系數(Total Active Reflection Coefficient,TARC)和輻射效率的表示方式。利用矩陣特徵值分解(Eigenvalue Decomposition (EVD))可將TARC表示成天線反射功率矩陣特徵值的組合。我們利用此方法計算反射係數和輻射效率的最大值和最小值,並分析反射係數和輻射效率的特性如何隨著天線埠饋入不同相位訊號時有所改變,我們也分析不同天線匹配網路如何影響此反射系數和輻射效率。 最後我們提出兩組適用於任意大角度分佈入射角度(Large Angular Spread Angle-of-Arrival)的相關係數近似公式。利用此兩組公式，我們進一步計算含天線偶合效應的相關係數。基於此兩組近似公式的計算方法不僅可以有效降低計算複雜度，在精確度上也有不錯的表現。

In the thesis, we focus on two electromagnetic analysis strategies to evaluate the performance of multiple antenna systems. The first is composite analysis of radiation efficiency. The second is a new calculation method of antenna spatial correlation. All case studies are simulated using dipole antennas.

First a composite analysis on total active reflection coefficient (TARC) and radiation efficiency are conducted.They can be described as the eigenvalues combination of antenna reflection power matrix utilizing eigenvalue decomposition (EVD).We not only evaluate the maximum and minimum value of TARC and radiation efficiency,but also their changes in characteristics when the antenna ports excite signals with different phases.Furthermore the investigations on how antenna termination networks influence TARC and radiation efficiency are also analyzed . We further propose two new approximate antenna spatial correlation formulations which are suitable for arbitrary large angular spread angle of arrival (AoA) distribution. By using these two formulations, we further calculate spatial correlation incorporating antenna mutual coupling. Time complexity can be reduced and it still maintain good accuracy by utilizing the calculating method based on these two approximate formulations.