射电天文望远镜的焦面阵设计

Design of focal plane array of radio telescope

为使射电天文望远镜的视场得到扩大,分析望远镜的视场时对天线的反射面提出共形网格剖分法,对物理光学法的常规计算方法进行了改进,使计算精度得到提高,且剖分网格少.采用改进的算法计算了WSRT望远镜的焦面场,并根据计算结果设计了WSRT望远镜的致密焦面阵结构;用共轭匹配法对阵列单元加权、计算相应的远场方向图,并与采用单个馈源时的远场方向图作比较.结果表明采用致密焦面阵能扩大视场并保证视场连续,增益也得到提高.

In order to increase the field of view （FOV） of the radio telescope, a new grid method named the conforming grid was proposed when the FOV of the telescope was analyzed. With this grid, the physics optical （PO） method is more accurate and fewer grids are needed compared to the conventional PO method. With the modified method, the focal field of WSRT telescope was computed. Based on the result, the dense focal plane array was designed for the telescope. The weights of focal plane array were given by the conjugate field method and the far fields of WSRT were computed. It is proven that a wider FOV, higher gain and aberration correction are obtained by dense focal plane array compared to the single feed.