空气腔对RFID读写器天线性能影响的研究

The impact of air cavity on the performance of RFID reader antenna

依据空气腔在滤波器和微带贴片天线中的成功应用,将其引入RFID读写器天线,针对工作频率和带宽特性进行研究.天线采用在介质板中间适当挖空的方法,使其形成一个矩形空气腔,从而调节谐振频率、提高阻抗带宽和辐射特性.相比较没有空气腔的天线性能指标为:在S11≤-10dB时,阻抗带宽从13MHZ增加到51MHz;AR≤3dB时,轴比带宽从7MHz增加到13MHz;天线增益从4.79dB增加到了6.34dB.

Air cavity is applied to RFID reader antenna and the frequency and the bandwidth of RFID reader antenna are studied based on the successful applications of air cavity to the filter and the micros- trip patch antenna. To form a rectangular air cavity, the middle part of the antenna＇s dielectric-slab was hollowed in order to regulate resonant frequency and improve impedance bandwidth and radiation charac- teristics. Compared with the antenna without the air cavity, the antenna impedance bandwidth increases from 13 MHz to 51 MHz under the condition of S11≤-10 dB,the axial ratio bandwidth increases from 7 MHz to 13 MHz under the condition of AR≤3 dB,and the gain increases from 4.79 dB to 6.34 dB.