作者：周勇1,2,3, 郁佳婧1, 陈挺1
作者单位：1. 南京信息工程大学电子与信息工程学院, 江苏 南京 210044;
2. 江苏省气象传感网技术工程中心, 江苏 南京 210044;
3. 南京信息工程大学大气环境与装备技术协同创新中心, 江苏 南京 210044
关键词：近场-远场变换;平面近场测量;等效磁流法;共轭梯度法;快速傅里叶变换
摘要：
近场测量是一种重要的天线测量方法，该文采用一种等效磁流法的平面天线近远场变换方法，根据近场平面上测量的电场分布计算天线口径面上的等效磁流分布，进而得到空间任意位置的天线辐射分布。首先由等效原理建立天线口径面与近场扫描面的关系，得到表示近场与等效磁流的电场积分方程（EFIE）。通过矩量法（MOM）建立矩阵方程，引入共轭梯度（CG）法和迭代法求解；再利用快速傅里叶变换（FFT）法，提高运行速度；最后根据格林公式计算得到天线远场方向图。为降低矩阵运算的工作量，提升测试工作效率，只对与天线辐射传播方向两个正交平面上进行采样测量，得到相应的E面和H面方向图。最后通过仿真验证方法的可行性，结果表明，等效磁流法反演的天线方向图和实际方向图在主瓣附近110°范围内具有良好的一致性，可以应用于天线近场测量。
Research on antenna near field measurement based on CGFFT and equivalent magnetic current method
ZHOU Yong1,2,3, YU Jiajing1, CHEN Ting1
1. School of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China;
2. Jiangsu Technology and Engineering Center of Meteorological Sensor Network, Nanjing 210044, China;
3. Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China
Abstract: Near field measurement is an important method for antenna test. A near filed-far field transformation using equivalent magnetic current method is presented in this paper. The magnetic current distribution on the fictitious planar surface on the antenna aperture is calculated from the electric field distribution measured on the near-field plane, with which the antenna radiation pattern in any location can be obtained. Firstly, the relationship between the antenna aperture surface and the near-field scanning surface was established according to the equivalent principle, and the electric field integral equation (EFIE) representing the near field and the equivalent magnetic current is obtained. Method of moments (MOM) was used to get the matrix equation, and the conjugate gradient (CG) method and iteration method were employed to solve the matrix equation. The fast Fourier transform (FFT) method was used to improve the calculation speed. The antenna pattern was calculated according to the Green formula. In order to reduce the matrix computing time and improve test efficiency, only two orthogonal slices of near-filed along the propagation direction were measured, and antenna pattern with E-plane and H-plane were calculated correspondingly. Finally, the method was validated with simulation. The simulation results show that the computed antenna pattern has good agreement with the analytic results over a range of 110° around the main beam. The method is applicable to antenna near field measurement.
Keywords: near field-far field transformation;planar near field measurement;equivalent magnetic current method;conjugate gradient method;fast Fourier transform
2020, 46(1):18-23 收稿日期: 2019-06-18;收到修改稿日期: 2019-08-31
基金项目: 国家自然科学基金资助项目(61601231)；江苏省自然科学基金资助项目(BK20140999)；江苏省气象传感网技术工程中心开放基金资助项目(KDXG1302)
作者简介: 周勇(1982-),男,安徽滁州市人,硕士生导师,博士,研究方向为天线测量
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