Subjects: Astronomy >> Astrophysical processes submitted time 2022-11-17 Cooperative journals: 《天文研究与技术》
Abstract： Shadowing effects is one of the main consideration factors in designing complex system with multiple antennas. There will be 373 sets of antennas in Mingantu Station, after completing the construction of the program Meridian II equipment of National Major Science and Technology Infrastructure. Limited by test site, model complexity and computation, shadowing effect is usually hard to measure and to predict especially for electrically large-size structures. The observed solar radio data on S/C/X bands between 2017 and 2020 by MST (Mingantu Solar Radio Telescope), present the shadowing effect with the 20m antenna and remote hills as obstacles. The observed data with shadowing effect can be divided into antenna area, atmosphere area and hills area with different shadowing characteristics. Based on the prediction method of single knife-edge diffraction loss recommended by ITU-R P.526-15, a model of 20m antenna reflector is built, the shadowing effects on S/C/X-bands are simulated, and the results show agreement with those of observation. From simulation and observing results, shadowing effects are related with wavelength, obstacle character, distance and angle among obstacle, source and receiving antenna, the receiving antenna’s beam, and dynamic range of receiving system, etc.
Subjects: Astronomy >> Astrophysical processes submitted time 2017-10-11 Cooperative journals: 《天文研究与技术》
Abstract：明安图射电频谱日像仪(Mingantu Ultrawide SpEctral Radioheliograph, MUSER)是新一代具有高时间、高空间、高频率分辨率的太阳专用射电望远镜，采用综合孔径原理成像，所以幅度和相位是决定最后成图质量的关键因素。天线的相位方向图会影响日像仪输出的幅度和相位，根据日像仪的馈源设计和综合孔径原理，针对明安图射电频谱日像仪天线数目多，且为户外环境，根据天文观测须经常测试天线性能的特点，给出了基于相关结果测量日像仪天线相位方向图的方法，该方法可以直接通过日像仪的相关输出结果高效准确地得到天线的相位方向图。对MUSER-I天线的相位方向图进行了测量和分析，同时分析了天线相位方向图对日像仪成像的影响，为得到高质量的太阳图像提供了参考和保障。
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