本研究之主旨，乃提出兩款以自混波形式之混波器實現可應用於圓極化天線之量測系統。此量測系統設計初衷為使天線量測更為簡易，並解決現今常用量測系統無法量測主動式天線之極化特性困難。本論文共提出兩種系統架構，經過公式推導及實驗驗證，此兩種架構之表現皆能與設計初衷符合。
定義極化之關鍵條件為:兩互相垂直之電場之相位差及振幅，若可量測此兩關鍵之條件，即可定義天線之極化特性。吾人利用數學推導方式，架構整個量測系統。經觀察數學公式，進一步導出量測相位和量測振幅之電路模型，並分別提出兩種不同的量測系統電路架構。
首款量測相位系統，乃將低雜訊功率放大器、威爾金森功率分配器、混頻器、接收天線等構成元件連接整合成一量測系統，最後利用三用電表得到最後結果，並經過數學換算得到最後量測結論。其次，以前一款設計為基礎，使用不同電路佈局實現一款量測振幅系統。兩款系統經實測驗證，均顯示推論模擬公式與量測響應吻合。使用已知圓極化天線進行該兩款圓極化系統之量測，確實可量測並定義出圓極化之特性，故實驗結果與初衷吻合。經實驗證明，此兩款量測系統可定義天線之極化特性。

A circular polarization measuring system using self-mixing mixers applicable to CP active antenna concept was proposed and demonstrated in this thesis. The design goal is to simplify the antenna polarization measurement as well as to tackle the common problem of measuring the polarization of the active integrated antenna (AIA). It consists of two different configurations for measuring the magnitude and phase difference between two orthogonal E-field components.
To realize the proposed systems, the basic principle of the antenna polarization is firstly explored. The closed form equations, describe the relationship between antenna polarization and characteristics of the two orthogonal E-field vectors, are then determined accordingly. Based on the general formula, the two corresponding sub-systems for measuring the magnitude and phase difference of two E-field vectors are built and tested.
In the experiments, all core components such as low noise amplifier, Wilkinson power divider, mixer and receiving antennas are integrated as a whole for measuring the phase difference parameters. The raw data were manipulated based on general formulae to achieve final results. Base on the first design, the amplitude measurement system was built by slightly modifying the structure. Two sub-systems were utilized to measure some typical linearly and circularly polarized antennas. The results were compared to the one obtained by commercial measurement system. All measured results are in good agreement, which validates the design concept.

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