中文摘要：

提出了一种由两组正交放置的双L天线构成的新型圆极化射频识别读写器天线，有效地克服了平面倒F天线缝隙加载等技术带来的两个谐振点频率相差大、带宽较窄的缺点。利用时域有限差分法对天线仿真和优化，天线的两个频段的中心工作频率分别位于我国分配给RFID技术使用的两个超高频频段内。在ISO／IEC推荐RFID使用频段内的反射损失小于．10dB，天线的相对带宽达到17％以上。优化3dB电桥馈电网络设计，在工作频段内为天线提供等功率、相位差为90°的激励信号，天线具有圆极化特性．仿真和测试结果表明：优化天线设计很好地缓解了天线带宽增加和天线效率下降的矛盾，在我国为RFID分配的频段内具有高的天线效率，并能够工作在ISO／IEC推荐使用的频段内，达到实用化要求。

英文摘要：

A novel antenna and feed networks were proposed for dual frequency of 840MHz-845MHz and 920MHz-925MHz application which was allocated for RFID use in China. The antenna is composed of two dual-L antennas orthogonally placed on a ground plane. Due to enhanced width, the antenna also can be applied to ultra high frequency of 860MHz- 960MHz that is proposed for RFID use by ISO/IEC. The feed networks which are used to attain circular polarization characteristics of the antenna were introduced to control horizontal and vertical radiation current flows for each dual-L antenna respectively. Simulation and measurement were performed and the frequency band with a return loss less than -lOdB was achieved.