长偶极子和大磁环构成的新电磁矢量传感器多参联合估计研究

Next-generation wireless communications, seismic exploration, radar and other relevant fields are more and more demanding on smart antenna technology. For high-precision detection and characterization of radio frequency (RF) signals, the antenna should be sensitive to both the direction-of-arrival and polarization of incoming electromagnetic waves. In this context, electromagnetic vector sensors have attracted more and more attention. In vector-sensor array signal-processing algorithm development, the existing literature always assumes the three dipoles and three loops that constitute a complete electromagnetic vector-sensor (EMVS) are, respectively, "short" dipoles and "small" loops. Such electrically "short" dipoles and magnetically "small" loop-antennas have very small input impedances, rendering them, as well as the resulting EMVS, to be inefficient radiators. Practical antennas, i.e. electrically "long" dipoles and magnetically "large" loop-antennas, have notably larger input impedance, hence making them better radiators. Our project will 1) first establish the measurement model (i.e., array manifold) of a new EMVS consisting of three identical, but orthogonally oriented, electrically "long" dipoles, plus three identical but orthogonally oriented magnetically "large" loops — all spatially collocated in a point-like geometry; 2) develop the corresponding algorithms in closed form to estimate incident sources' azimuth-elevation direction-of-arrival (DOA) and polarization; 3) investigate various collocated combinations of orthogonally oriented "long" dipole(s) and/or "large" loop(s) and develop their corresponding DOA and polarization estimators. The expected results of our project will enrich the theory of vector-sensor array signal processing.

下一代移动通信、地震勘探、雷达等领域对智能天线的要求越来越高。天线对信号高精确的检测和表征不仅需要感知信号的方位信息还依赖极化信息的辨识。在这个背景下电磁矢量传感器越来越受到人们的关注。现有矢量传感器阵列信号处理的文献假设构成电磁矢量传感器的三个偶极子是“短”偶极子，三个磁环是“小”磁环。然而，这种电“短”偶极子和磁“小”环形天线具有非常小的输入阻抗，使得它们以及由它们所组成的电磁矢量传感器成为低效辐射器。实用的天线，如电“长”偶极子和磁“大”环形天线具有明显较大的输入阻抗，因此使它们辐射及接收效率更高。本项目将1）建立一个基于“长”偶极子和“大”磁环的新电磁矢量传感器测量模型; 2）开发相应的闭式算法来估计入射源的方位角仰角波达方向和极化; 3）研究正交的“长”偶极子和（或）“大”环的各种并置组合并开发它们相应的DOA和极化估计算法。本项目的研究成果将丰富矢量传感器阵列信号处理相关理论。

下一代移动通信、地震勘探、雷达等领域对智能天线的要求越来越高。为了实现更好的电“长”偶极子和磁“大”环形天线辐射及接收效率，本项目主要对长偶极子参数估计、大环形天线参数估计、波束滤波器等方面开展系统深入的研究。具体成果如下：1）提出了一种在长偶极子数据上使用短偶极子算法的算法范式，推导了模型失配下的克拉美罗界；与现有的长偶极子三元组算法相比，所提出的算法具有更好的估计精度，可处理两个信号，需要较少的先验知识并提供更宽的波达方向估计扇区。2）使用简单的小环形天线三元组算法获得的粗略估计值作为初始化，开发了一种迭代调整算法，并推导出了模型失配下的克拉美罗界。3）分析了方向性顺序如何影响三元组的“空间匹配过滤器”光束的定向转向能力，揭示了哪些方向性顺序允许波束模式在任何方位角方向上具有完全机动性，哪些方向性顺序则不能。. 在该项目的支持下，本课题组已发表/录用学术论文8篇，其中SCI期刊论文5篇，EI会议论文3篇。申请发明专利3项。. 本项目的相关研究成果丰富了矢量传感器阵列信号处理相关理论。