本論文研究了兩項與天線系統相關的主題。由於車用通訊系統的全向性天線，有傳輸距離較短和易受干擾等問題，所以吾人提出一種平面式波束掃描天線設計來克服這些困擾。該本天線採用週期型洩漏波天線設計的原理，將兩組週期型洩漏波天線垂直交叉擺放，使用矩形微帶面和增加凹槽的方式加強兩組天線彼此間的隔離度，然後由四個微帶面的邊緣處作射頻能量饋入。並用量測驗証波束傾斜的角度和方向，以達成空間上的多樣性；為了實現輻射波束方向的控制，我們利用一個一對四的射頻開關作射頻訊號的切換，來選取適當的饋入端，決定傳輸訊號所使用的波束方向。
因應無線通訊用手持設備的增加，天線需求量增大。製造商進行品管檢測時，若利用傳統的向量網路分析儀量測天線的反射係數，因為儀器貴重，在做大量檢測時並不恰當，因此在本研究中開發新型的簡易式天線反射係數量測系統。我們使用不同類型的天線以該系統量測，並與向量網路分析儀量測的反射係數大小進行比對，驗證簡易式系統的準確性，並針對系統中可能造成誤差的來源進行分析以及討論。在系統的改良上，我們亦提出一個可量測訊號相位的系統架構，可進一步取得天線反射係數中的相位資訊。

This thesis investigates two antenna related topics. Conventionally, because the automobiles use omni-directional antenna for communication systems, which may suffer limited communication distance and interference. A Planar one-to-four beam switching antenna is proposed to solve these issues. Two periodic leaky wave antennas are arranged in a cross configuration. In order to improve the isolation performance of the cross leaky wave antenna, we reshape square patches into rectangular ones. Fillisters are also added between patches to increase isolation. The leaky wave antenna comprises four driven patch elements, which are connected via a one-to-four RF switch and five parasitically coupled patch elements. By selecting a specific through path, RF power is fed to one of the driven patch elements to produce a directive beam. The proposed beam switching antenna can help increase spatial diversity.
Due to the growing popularity of personnel mobile communication devices, antenna designs are in great demands. In mass production, it is expensive to evaluate the reflection coefficient of antennas using a traditional network analyzer. Therefore, this research attempts to develop a new antenna impedance measurement apparatus composed of a VCO, a power detector and a circulator. A curacy in the magnitude of measured reflection coefficient is estimated by comparing results of three different types of antennas with network analyzer measurement results. A more sophisticated system, which in dudes a phase shifter, a voltage controlled attenuator and a rat-race hybrid, is proposed to measure the phases of reflection coefficients.

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