波达方向（DOA，Direction of Arrival）、频率和极化以及其它参量是空间传播电磁波的重要特征，是认识空间电磁波所携带信号的重要参量，因此，利用阵列天线对包括波达方向、频率和极化等参数的估计广泛应用于雷达、声纳、通信、地震勘探和医学成像等多个领域。在对电磁波进行波达方向估计的研究方面，本文提出了可以把相位差信息转换为强度信号的环天线并对其进行了实验及分析，本文主要包括以下内容：1） 本文提出了可以把相位差信息转换为强度信号的闭合环天线，并通过实验验证了这一性能。这一性能使得闭合环天线同时对电磁波的极化方向和相位差两个成分敏感，其输出值随着电磁波不平衡作用的增强而增加。在测量波达方向的应用中，使用闭合环天线可以减少阵列天线的数量，并且通过增大天线单元间距可以减弱阵列天线的互耦，而不影响测量波达方向的准确性。2） 本文研究了互耦对天线输出信号的影响，结果表明：在电磁波不同的到达方向角条件下，天线之间均存在明显的互耦；两天线距离大于波长一半或重叠面积比例小于0.2时，它们间的互耦变得很弱。在实际应用中，可以根据本文结果对闭合环天线的间距和重叠面积进行调整，以减弱天线间的互耦。3） 为了验证本文提出的环天线的方向性能，根据HFSS天线设计流程，仿真模拟了环天线的三维角度变化曲线，结果表明：仿真结果和实验结果基本一致，证明了闭合环天线设计的合理性和结果的可靠性。

DOA（Direction of Arrival）, frequency, polarizations and other parameters are important characteristic of the electromagnetic wave propagating in the space. By measuring these various characteristics of received waveforms, we can draw conclusions about the events that caused them. Thereby, using arrays to estimating DOA, frequency , polarization and other parameters are widely used in radar, sonar, communication, seismic exploration and medical imaging, and other fields. Loop antenna that can transform the phase difference information into an intensity signal is proposed and experimentally studied. This paper mainly include the following content:1） Closed loop antenna that can transform the phase difference information into an intensity signal is proposed and experimentally studied. This ability makes the closed loop antenna be simultaneously sensitive to two constituents of electromagnetic wave: polarization direction and phase difference. Output of the closed loop antenna increases with the unbalanced effect of microwave. In the application of DOA, using closed loop antennas can both reduce the number of antenna units and the mutual coupling of antenna array.2） We studied the influence of mutual coupling on the output of antenna through experiment, the result shows that: there are obvious mutual coupling between antenna for different direction of angel of electromagnetic wave. When the spacing between two antenna is more than half of wavelength or the overlapping ratio is less than 0.2, the mutual coupling will become very weak. In the application of DOA, using closed loop antenna can reduce the mutual coupling according to the results of our experiments.3） In order to validate the direction performance of the proposed loop antenna. According to the HFSS antenna design process, the 3 d Angle change curve has been simulated of the loop, and the results show that: the simulation results and experimental results are coincide well, it proves that the design of loop antenna is reasonable and the experimental results are reliable.