Summary
International Symposium on Antennas and Propagation
2009
Session Number:2B4
Session:
Number:2B4-4
Triple Loop Antennas with Shifted Gate Arrangement for LF-RFID Systems Optimized by Evolution Strategies
Sarayoot Todnatee, Chuwong Phongcharoenpanich, Danai Torrungrueng,
pp.421-424
Publication Date:2009/10/21
Online ISSN:2188-5079
Summary:
The animal identification in farm is one of the most promising applications of Radio Frequency Identification (RFID) system at the low frequency (LF) band (134.2 kHz). Conventionally, the rectangular and the circular loops are used as the reader antennas. However, these antennas cannot communicate with tags for some tag orientations [1],[2]. For the antenna in walk-through with shifted gate arrangement, the cancellation of magnetic field distribution in the middle region of the antenna gates can be mitigated[3]. In this paper, triple loop antennas arranged as a shifted gate are proposed to improve magnetic field distribution in the region occupied by two shifted gates. The enhanced communication performance is due to the increase of numbers of loop antennas (from two to three) with appropriate shifted gate arrangement. Optimum parameters of the proposed triple loop antenna are obtained using evolution strategies (ES) [4] and the Numerical Electromagnetic Code (NEC) [5]. The evolution strategy is an optimization tool of evolution in nature which is one of family of evolutionary algorithm processes. The optimized antenna is fabricated and measured its performance. Simulated and measured results are-in good agreement.