Designs of RFID Reader and Tag Antennas

• Main Authors: Kuo-hsien Wu, 吳國賢
• Other Authors: Chang-Fa Yang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/59785959246224410641

碩士 === 國立臺灣科技大學 === 電機工程系 === 97 === 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.