Wearable Tag Antenna Designs for UHF RFID Applications

• Main Authors: LIANG, SHU-YAO, 梁述堯
• Other Authors: Sim, Chow-Yen-Desmond
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/5898xe

碩士 === 逢甲大學 === 產業研發碩士班 === 105 === In this thesis, two UHF (ultrahigh frequency) RFID (radio frequency identification) wearable tag antennas with good reading range are presented. The first proposed antenna is a small size tag antenna which is designed for racing pigeon ring applications. The structure of this proposed tag antenna I is a closed-loop type printed on a 30 × 8 mm2 polyimide film of thickness 0.063 mm. Thus, it can be wrapped into a double layer plastic cylindrical ring of size similar to those used for racing pigeon. By simply tuning the inner width of the loop, good conjugate matching between the tag chip input impedance and the tag antenna can be achieved. When mounted onto a real preserved dried pigeon feet specimen, the measured impedance bandwidth of the tag antenna I was 901–929 MHz. Further experimental results have also shown that the proposed tag antenna I has a maximum reading range of up to 50 cm. The second proposed tag antenna is a low-profile UHF RFID tag antenna designed for wristbands in healthcare applications is proposed. The radiator is based on the open-slot cavity technique that is composed of a slotted patch (double-T slots) loaded onto a flexible open cavity. The proposed slotted design can easily allow the tag’s input impedance to be tuned to the complex impedance of typical UHF RFID chips. The proposed tag antenna II has a size of 86 mm × 25 mm × 1.6 mm (0.26 λ0 × 0.07 λ0 × 0.004 λ0) at 915 MHz, and it can yield maximum reading range of 8 m (in free space condition) and 6.6 m (when located on human wrist).