电特大天线增益的高效求解

Efficient Solution for Extremely Electric Large Antenna Gain

为解决电特大天线辐射特性计算效率低的问题,提出并实现了一种基于多极子的聚集思想快速求解远场信息的高效并行算法.根据目标在并行多层快速多极子中几何树的特征,提出高层远场模式直接聚集,并且按行并行插值的混合MPI-OpenMP并行计算方案.将该算法应用于大射电天文望远镜FAST(five-hundred-meter aperture spherical telescope)的远场方向图和增益的计算,通过与等效电流直接积分法计算对比展示其计算精度与效率.结果验证该算法的远场辐射特性计算精度,且同等远场计算任务量下,平均单方向计算效率提高近万倍.

An efficient parallel algorithm to accelerate the calculation of the far-fields was proposed and implemented for solving the electric large antenna radiation problem, based on the upward pass or the aggregation phase of the parallel multilevel fast multipole algorithm （MLFMA）. According to the geometry tree structure of the parallel MLFMA, an efficient hybrid MPI-OpenMP parallelization algorithm was designed with the direct aggregation of coarser level far-field radiation pattern and parallel in-row interpolation. The computation of far-field radiation pattern and antenna gain of the extremely large parabolic reflector of FAST by this algorithm shows the accuracy and efficiency of the parallel program, compared with the computation by the equivalent current direct integration method. The numerical results demonstrate that the presented approach has good accuracy for the radiation characteristics, and the computational efficiency has improved about ten thousand times for single direction under same far-field calculation task compared to the equivalent current direct integration method.