Design and Implementation of the Active Antenna System for 2.4 GHz Application

• Main Authors: Chih-Chuan Chen, 陳誌權
• Other Authors: Man-Long Her
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/42570121499981081828

碩士 === 逢甲大學 === 資訊電機工程碩士在職專班 === 96 === This thesis will study the coordination of the antenna and active circuit applied in 2.4 GHz communication system, to solve the loss of transmission cable between system end and antenna, and to boost the communication range and efficiency. Tough this study does limited contributions to general communication system; however, it does a lot to RFID system. Because 1 dB loss in RFID system makes a big influence on reading rate of the overall system. Therefore, the ultimate purpose of this paper is to study how to improve the rate of RFID reader. There is no room to make even a very tiny mistake when managing money and articles; this is the main reason to synthesize antenna and amplifier to be an active antenna system. We would also like to investigate the production of line antenna and round antenna. Finally we will focus on the difference of electronic RF switch and amplifier module that made of passive components. Though it does not contribute a lot to whole RFID industry, it does help a lot for the use in specific environment such as barrier-free customs clearance system and reading rate of minimized TAG will be upgraded to 100%. The data will be tested by a reflection-free lab and provides information for overall circuit. This study will aim at 2.4 GHz and could be extended to other bands if this study is proved. Due to regulations given to RFID system, the standard output power is 36dBm. The reader outputs 30 dBm and 6dB gained by the antenna. However, the output of the reader is fixed at 30 dBm, only the change of the gain in antenna will be possible. It’s very difficult to boost the gain in a limited room. By synthesizing the antenna and active circuit to be an active antenna system, the gain will be increased to 31 dBi, from 11 dBi in a loop antenna, a tremendous boost in the gain of the antenna. As this system will work as a two-way system, it’s necessary to study the identification of the transmitter and the receiver. That’s why electronic RF switch and passive power distributor are available to choose, the efficiency and loss will be discussed carefully in this essay.