高交叉极化隔离度的液晶极化相控阵天线设计与实现

Design and implementation of an polarization phased array antenna with high cross-polarization isolation based on liquid crystal

针对小型化、低成本极化相控阵雷达应用背景,提出了一种基于液晶材料的高交叉正交极化隔离度的极化相控阵天线。与传统极化相控阵天线相比,该设计不需要成倍增加的收发组件和复杂的移相馈电网络。基于液晶传输线移相器特点,结合缝隙耦合辐射原理,提出一种基于斜交耦合缝隙的交叉极化抑制结构,在提升天线单元主极化辐射性能的同时,抑制交叉极化辐射幅度。天线阵列采用由中心向两侧180°反向馈电形式,进一步提升交叉极化抑制比,同时可以实现极化和波束的联合重构。样机实测表明,天线扫描角度可达±40°,增益最大可达16.8 dB,效率高于66%,法向交叉极化隔离度可以达到33.3 dB,法向波束旁瓣最大抑制可以达到36.3 dB;展示了液晶极化相控阵天线的实用性,并且具有低成本、低功耗以及结构简单的特点。

Aiming at the application background of miniaturized and low-cost polarization phased array radar application,an orthogonal polarization phased array antenna with high cross-polarization isolation based on liquid crystal is proposed.Compared with the traditional polarized phased array antenna,this design does not need to multiply the transmitter and receiver components and complex phase-shifting feed network.Based on the characteristics of liquid crystal transmission line phase shifter and the principle of slot coupling radiation,a cross-polarization suppression structure based on a inclined cross coupling gap is proposed,which not only improves the radiation performance of main polarization,but also suppresses the radiation amplitude of cross-polarization.A 180°reversed feed from the center of antenna array to both sides is adopted to improve the cross-polarization suppression ratio,and at the same time,the joint reconfiguration of polarization and pattern can be realized.The actual measurement of the prototype shows that the scanning angle of the antenna can reach±40°,the maximum gain can reach 16.8 dB,the efficiency is higher than 66%,the isolation of cross-polarization of boresight beam can reach 33.3 dB,and the maximum suppression of boresight beam sidelobe can reach 36.3 dB.It is shown that the liquid crystal polarized phased array antenna is practical,and has the advantages of low cost,low power consumption and simple structure.