本論文提出三款被動式UHF射頻辨識系統之標籤天線，其一為可附著於金屬表面之標籤天線，乃應用間隙電場耦合之方式來饋入能量至天線的輻射體，並大幅降低標籤附著物之金屬表面對於天線本體的影響。其二為微型化標籤天線，可將其內建於行動通訊裝置中。為了有效提升標籤的讀取距離，乃分別應用集總與準集總電路進行阻抗匹配。其三是為了滿足近場與遠場之辨識需求，設計一款被動式近遠場標籤，不僅具有遠距離讀取功能，亦能符合近場辨識之應用。
另外，本論文亦設計兩款UHF射頻辨識系統之讀取器天線，其中一款為具備較強近場磁場之環形天線，可有效提升物件標籤之辨識距離，相當適用於近場辨識系統上，本研究即使用此款近場天線進行智慧型書架之整合，可以有效達到圖書管理之目的。本論文之另一款讀取器天線為具有高增益及高指向性之平面式準八木天線，改善了傳統準八木天線頻寬過窄之缺點，並且利用其高指向性之特性完成一讀取器天線系統，可對特定方位進行辨識之功能。

This thesis proposes three UHF passive tag antennas for radio frequency identification (RFID) applications. The first tag antenna mounted on a metallic object uses a gap coupling structure to provide RF energy to a radiator so that effects from metallic surface to the antenna can be reduced significantly. The second tag antenna is designed to be built in a portable device, where both quasi-lumped and lumped circuits are applied to achieve a conjugate match between the tag antenna and IC. Therefore the reading range may be enhanced. To have both the near- and far-zone operations, the third passive tag antenna with is thus proposed to meet those requirements by having a loop-type feed.
On the other hand, two RFID reader antennas operating in UHF band are also presented in this study. A loop antenna having large intensity in magnetic field has been designed for reading item-level tags. This reader antenna may be used in the near-zone RFID system, such as an intelligent bookshelf for book management. Another reader antenna design is a quasi-yagi antenna where a compact antenna with a suitable gain is proposed for identify an object in a specific direction.

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