Study of Reader Antenna for RFID System

• Main Authors: TSAI, MING-HONG, 蔡明泓
• Other Authors: LIN, MING-SHING
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/w72x4v

碩士 === 國立雲林科技大學 === 電機工程系 === 106 === The purpose of this thesis is to improve the reading accuracy of the radio frequency identification (RFID) reader of a sports event system.Our strategy for this purpose is to employ a proposed circularly polarized (CP) ultra-high frequency (UHF) antenna as the reader antenna so that, when low frequency/high frequency (LF/HF) signals coming from the floor mat are too weak to identify by the LF/HF reader, the designed UHF antenna can receive more identifiable UHF signals.By doing so, the reading range of the sports event system can be enhanced. First, an 860–960 MHz UHF band single-port-fed CP antenna was designed to replace the existing linearly polarized (LP) RFID reader antenna of the sports event system.Four such UHF CP antennas cleverly arranged as a 2×2 array antenna were connected with a specially designed one-to-four power divider to maintain good CP radiations.The return loss, insertion loss, output phase, and isolation of the power divider, as well as the return loss, gain, and radiation patterns of the array antenna were all investigated. Next, the radiation patterns of the designed 2×2 CP array antenna with those of a 2×2 LP array antenna when operated in sports events were compared.From these radiation patterns, the effective reading ranges under different antenna placements for both cases were then evaluated.They include the reading distance, readable beam angle, and coverage range.The reading distance and coverage range were verified outdoors.The enhancement of the reading distance using multiple antenna readers for sports events was discussed. In short, an UHF reader antenna has been proposed for use in a sports event system.The accomplished coverage range and effective reading distance have been found large enough to compensate those unachievable by the LF/HF subsystem.