宽带星载DBF相控阵天线设计与实现

Wideband DBF phased array antenna on LEO satellite

针对低轨卫星通信天线波束"等通量"覆盖的赋形要求,采用遗传算法对天线阵列进行了多目标平衡优化综合。根据SHA阵和波束覆盖的空间旋转对称性,在波束空间和阵元空间内进行阵元分组,将波束形成矩阵自由度降为1/3,简化了遗传算法参数数量,为波束形成因子复用奠定基础。针对16波束宽带输入,利用DFT滤波器组、复用式波束形成网络、单音闭环校正等算法设计了分布式数字波束形成器和幅相校正单元,运算量降为原来的4.5%,节省硬件资源80%。最后首次完成了16波束61阵元星载DBF相控阵天线样机的研制,暗场测试结果表明波束增益达到等通量覆盖要求,验证了以上算法和工程设计的正确性与有效性。

Genetic algorithm with multi-objective optimization strategy was proposed to synthesize the antenna array on LEO satellite according to the requirements of iso-flux beams coverage. Based on the rotation symmetry of beam cover- age and elements distribution, antenna elements were partitioned into groups in beam space and element space, and just one third of beam forming matrix coefficients were independent. The simplicity of DBF matrix helped reduce the number of parameters in GA and design the hardware structure of DBF network. Generalized DPT filter bank, multiplex DBF computer and RF calibration in close-loop mode were adopted to design the DBF network, which can reduce the calculation by 95.5% and save the multiplier resource up to 80%. Ultimately a 61-channel phased array transmitter antenna with 16 simultaneous beams was designed. The measurements in anechoic chamber demonstrate that the phased array antenna has good performance of iso-flux beams coverage, which validates the rationality of algorithms and project implementation.