一种新型串并联馈电低副瓣ETC微带天线阵

A Novel Parallel-series Feeding Microstrip Antenna Array with Low Side-lobe for ETC System

设计并实现一种用于电子收费系统的四角缺元20单元微带天线阵列。天线阵采用道尔夫-切比雪夫分布,副瓣电平优于-20dB;采用三路功分器作为核心器件,与定向耦合器和威尔金森功分器组成一种新型串并联支路组合馈电网络,实现各端口不同比例功率分配,误差小于±0.5dB,各端口回损优于-15dB,隔离度优于18dB,相对带宽大于11%。样机测试结果与仿真值相吻合。馈电网络结构紧凑、灵活性强,适用于中等增益低副瓣平面阵列天线的馈电。

An unfilled-angle-rectangle 20 units patch antenna array applied to the ETC(Electronic Toll Collection) system is designed and realized.The Dolph-Chebysev distribution is adopted to design the aperture,and its side lobe level is better than-20dB.Besides of the directional coupler and Wilkinson power divider,a three-way power divider is introduced as the kernel to form a kind of novel parallel-series feeding network.The simulation and measurement results coincide and indicate that the following performances can be achieved: the error of various output power ratio of each port is less than ±0.5dB,the return loss of each port is better than-15dB,the isolation between two ports is better than 18dB,and the relative bandwidth is more than 11%.The feeding network has compact structure and high design agility,and it is adapted for the medium gain low side-lobe microstrip antenna array.