耦合对环形相控阵生成涡旋电磁波的影响

Coupling Effects on the Vortex Wave Generation of the Uniform Circular Array

该文研究了环形天线阵列生成具有轨道角动量的微波频段涡旋电磁波的过程中,天线阵列单元间的耦合对生成的涡旋电磁波的模式的影响.通过理论分析,以及基于矩量法的全波电磁数值计算,给出了在一定的条件下,耦合对生成的涡旋电磁波的模式数的影响.结果表明,当存在耦合的旋转对称性时,耦合不会对涡旋波的生成造成影响;而当不存在耦合的旋转对称性时,单元间耦合会使生成的涡旋波偏离理想结果.耦合对涡旋波的影响程度敏感于模式数、环形阵列半径、观测点方位.基于文中的参数,即使相邻单元间距大于两个波长,耦合也可能使模式数改变14%以上.

Uniform circular array(UCA)can generate vortex wave with orbital angular momentum(OAM)in microwave band,this paper studies the effects of the coupling among the units on the OAM modes.The effects are evaluated by analysis and numerical computation based on momentum method(MoM).The results show that,if the coupling among units is rotational symmetry,then the coupling will not affect the generation of the OAM-carrying vortex wave.But if the coupling among units is not rotational symmetry,then the coupling will affect it.The effects is influenced by the mode number,the radius of the UCA,and the azimuth location of the field.Based on the characteristics used in the paper,even if the distance between the neighboring units is larger than two wavelengths,the mode number can be changed by more than 14%.It is significant for UCA design for vortex wave generation.