In this letter, we propose a wideband rectangular loop tag antenna for ultra-high frequency radio frequency identification library management systems.The proposed antenna has a small matching loop for conjugate impedance matching with the impedance of a tag IC. The impedance bandwidth of the proposed antenna is broadened by lengthening the vertical sides of a rectangular loop. We considered the effects of books in designing the tag antenna. The optimized tag antenna, which is 35 mm × 90 mm in size, has a wide impedance bandwidth of 170 MHz for S11 less than −10 dB. The maximum reading distance of a single tag is about 5 m, and the concurrent reading distance of 19 arranged tags is 1 m. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1439–1445, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25219
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