一种金属覆盖的超高频射频识别读写器天线

UHF RFID reader antenna of metallic cover layer

研制了一种适用于UHF RFID（ultra high frequency radio frequency identification）读写器的宽频带高增益微带天线。该天线基于自制的Z型六角铁氧体材料,在实现天线小型化的同时通过引入较大的磁损耗来展宽天线阻抗带宽,附加开窗的金属覆盖层可以达到提高天线增益的目的。测试结果表明,该天线具有较好的性能,工作于915MHz时,VSWR〈2的阻抗带宽达到29 MHz,最大辐射方向的增益达到3.6 dBi。所设计的天线能满足北美UHF RFID（工作频段：902-928 MHz）读写器的应用要求。

A broadband and high gain micro-strip antenna was developed for ultra high frequency（UHF） radio frequency identification（RFID） reader application. With the homemade Z-type hexaferrites, the antenna miniaturization could be obtained. Meanwhile, a wider impedance bandwidth could also be attained with the large magnetic loss of the hexaferrites. Additionally, the high gain could be obtained with a windowed metallic cover layer. Experimental results show that the reader antenna has better performance at the center frequency of 915 MHz： the VSWR is less than 2 in the bandwidth of about 29 MHz; the peak gain is 3.6 dBi at the maximum radiation direction. The presented antenna can well meet the application of the North America UHF RFID（with the band of 902-928 MHz） reader.