一种宽频带双圆极化微带天线阵列设计

Design of a Broadband Dual Circular Polarization Microstrip Antenna Array

为了支撑低轨卫星宽带数据下传需求,提出了一款宽频带双圆极化微带天线;采用微带天线作为基本辐射单元,基于层叠寄生贴片方式与加载空气腔方法展宽天线工作带宽并提高增益值,利用电容加载的三分支线定向耦合器对天线单元进行馈电进一步展宽天线带宽,并实现双圆极化辐射特性;单元电性能仿真结果良好,阻抗相对带宽为28.2%,轴比相对带宽达14.5%,峰值增益达到5.6 dBi;基于辐射单元进行4×4阵列组合,所设计阵列天线阻抗带宽覆盖7.7~8.9 GHz,同一单元不同极化与不同单元间端口间隔离度均≥15 dB,轴比在通带内均≤3 dB,方向图仿真与测试结果吻合良好,验证了设计方案的正确性。

To support the requirements of broadband data transmission from low orbit satellites,a wide band dual circular polarization microstrip antenna is proposed.The microstrip antenna is taken as the basic radiation unit,the antenna bandwidth based on the stacked parasitic patch and loaded air cavity methods is widened,and the gain value of the antenna is improved.The antenna unit is fed by using a capacitor loaded three-way branch directional coupler to further widen the antenna bandwidth and achieve the characteristics of the dual circularly polarized radiation.The simulation results of unit electrical performance are good,with an impedance relative bandwidth of 28.2%,an axial relative bandwidth of 14.5%,and a peak gain of 5.6 dBi.Based on radiation units,a 4×4 array combination is designed,with an impedance bandwidth covering 7.7~8.9 GHz.The isolation degree between different polarizations and ports of the same unit is not less than 15 dB,with a axial ratio of not greater than 3 dB within the pass band.The simulation results of the directional pattern are in good agreement with the testing results,the designed scheme is verified.