本論文目的為開發一款可涵蓋全向性的無線基地台天線，此無線基地台天線的特性需有較高的增益以達到更遠的工作距離。可藉由將單元天線陣列化，以壓縮其天線輻射場型進而提高其增益的方法達成。本論文第一部分提出一款微型化的迴圈天線，並將其組成一陣列天線。使用的微型化技巧包含向迴圈內部添加蜿蜒線段，以延長其電流路徑，產生的效果相當於增加其電感。微型化後的設計，其輻射效率可維持在87% ~ 92%。另一種使用的微型化技巧，是在其迴圈路徑上加入串聯之電感元件，以達到進一步縮減天線尺寸的效能。透過實作與量測，驗證具蜿蜒迴路與串聯電感元件的迴圈天線，可在不影響場型、犧牲部分頻寬與輻射效率的情況下，大幅將迴圈天線之共振頻率縮小，達到不錯的微型化效果，再透過漸進式傳輸線功率分配器將輸入訊號以等相位的方式，平均分至各個子天線來組成陣列天線，可增強其增益。
第二部分提出一款應用於提供大範圍中資料傳輸，具場型波束寬可調整的貼片天線，將接地面改為銅棒、貼片輻射體改為彎曲面，使輻射場型不再像一般平面式貼片天線有明顯之指向性，而能涵蓋更廣的輻射角度。可針對各種不同規模的涵蓋需求，經由調整貼片彎曲的角度，改變主波束的寬度，而能在不同的應用環境中彈性使用。

The main objective of this paper is to cover the development of a wireless access point antenna, which has an omni-directional radiation pattern. The requirement of a wireless access point antenna is to achieve a higher gain to have a larger coverage area. By adopting to array approach, the pattern can be compressed to raise the gain.
In the first part of this thesis, a miniaturized loop antenna is proposed. It is used to build up a four element array. The primary miniature technique used is adding meander line to the loop structure to extend the current path. The effect is equivalent to increase its inductance. With the miniaturized design, the overall radiation efficiency is around 87% to 92%. Another miniature technique used is to add series lump inductors on the loop path, which helps in reducing the antenna size. Through the implementation and measurement, we verify that an antenna with a meandered loop and series inductor elements can reduce resonant frequency significantly without disturbing its omni-directional radiation pattern. With a power divider made of tapered pair-wire transmission lines, signals can be delivered evenly to every element antenna in the same phase. This linear array design can substantially raise the antenna gain.
In the second part of this paper, a patch antenna with an adjustable beamwidth is proposed to comply with the needs of different operation environments. By changing the planar ground plane into a curved one, the radiation beamwidth can be controlled by the radii of the curved ground. The curved patch can also be employed to form an array of an omni-directional pattern.
Key words: miniaturized antenna, loop antenna, power divider, array antenna, omni-directional radiation pattern, WLAN, access point, patch antenna

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