![Cover Image for System.Linq.Enumerable+EnumerablePartition`1[System.Char]](https://coverimages.igi-global.com/images/search-article.png)
Beam Scanning UHF RFID Reader Antenna with High Gain and Wide Axial Ratio Beamwidth
Abstract
A novel ultra-high-frequency (UHF) RFID reader antenna is proposed, designed and measured. The proposed antenna is capable of 2-dimensional (2D) beam-scanning from 0° to 360° in the azimuth plane, and 0° to 40° in the zenith plane. The minima of the antenna's axial ratio (AR) follows its gain maxima during beam-scanning, resulting in an equivalent 3 dB AR beamwidth of over 136° for every phi cut. Moreover, the antenna's AR can be easily modified without affecting other parameters. It is shown experimentally that the antenna's 2D beam-scanning ability and the improved AR performance lead to better tag-reading results, improving the percentage of missing tags by up to 21.6% compared to a standard antenna which has a degraded AR and only supports 1D beam-scanning. In addition, the antenna needs no matching network and has a -10 dB return loss bandwidth from 860 MHz to 880 MHz.