互耦条件下涡旋电磁波目标方位探测方法

doi:10.12382/bgxb.2022.0480

摘要/Abstract

摘要：

采用均匀圆阵产生涡旋电磁波时,天线阵元的辐射方向图受到邻近阵元互耦的影响,发射信号幅度和相位会发生改变,进而影响目标方位探测性能。针对此问题,利用均匀圆阵互耦矩阵的循环对称性,通过傅里叶变换将互耦矩阵展开为模式域,描述阵元激励与轨道角动量模式数之间的关系,并提出一种基于轨道角动量的改进传播算子解耦合方位估计算法。与传统算法相比,该算法避免了谱峰搜索和大特征值分解;同时,利用涡旋电磁波原始导向矢量对回波信号进行处理,规避了贝塞尔函数近似带来的误差。仿真结果表明:模式域互耦矩阵有效补偿了互耦效应的影响;所提算法较传统传播算子算法相比估计精度更高,同时计算复杂度更低。

关键词: 涡旋电磁波, 互耦, 均匀圆阵, 传播算子, 方位估计

Abstract:

The use of a uniform circular array to generate vortex electromagnetic waves can lead to changes in the radiation pattern of antenna elements due to mutual coupling between adjacent array elements, causing variations in amplitude and phase that affect target azimuth detection performance. To address this problem, the mutual coupling matrix is expanded into the mode domain by Fourier transform using the symmetric circulant of the uniform circular array mutual coupling matrix. This allows for describing the relationship between array element excitation and the number of orbital angular momentum modes. Based on the above analysis, an improved propagation operator decoupling azimuth estimation algorithm based on orbital angular momentum is proposed, which avoids spectral peak search and large eigenvalue decomposition. Simulation results show that the mutual coupling matrix in the mode domain effectively compensates for the influence of the mutual coupling effect. Compared with traditional algorithms, the proposed algorithm boasts lower computational complexity and avoids errors stemming from Bessel function approximations.

Key words: vortex electromagnetic wave, mutual coupling, uniform circular array, propagator method, bearing estimation

中图分类号:

TJ43⁺4.1

章鸿运, 栗苹, 李国林, 贾瑞丽. 互耦条件下涡旋电磁波目标方位探测方法[J]. 兵工学报, 2023, 44(10): 3218-3226.

ZHANG Hongyun, LI Ping, LI Guolin, JIA Ruili. Target Bearing Estimation Using Vortex Electromagnetic Waves with Mutual Coupling[J]. Acta Armamentarii, 2023, 44(10): 3218-3226.

图/表 12

图1 均匀圆阵几何结构

Fig.1 UCA array geometry

图2 理想情况12阵元不同OAM模式相位分布图

Fig.2 Phase distribution of different OAM modes of 12 elements in ideal conditions

图3 阵列互耦馈电网络图

Fig.3 Schematic of the array mutual coupling feeding network

图4 均匀圆阵互耦OAM模式等效电路图

Fig.4 OAM mode circuit model of the UCA including mutual coupling

图5 涡旋电磁波探测原理图

Fig.5 Schematic diagram of vortex electromagnetic wave detection

图6 已校准和未校准的MUSIC算法空间谱

Fig.6 Calibrated and uncalibrated MUSIC spatial spectrums

表1 FEKO仿真参数

Table 1 FEKO simulation parameters

参数	数值
载波频率/GHz	24
波长/mm	12.5
阵元数	12
圆阵半径/mm	12.5
偶极子长度/mm	6.25
采样点	2701

表2 不同算法的计算复杂度

Table 2 Computational complexity of different algorithms

算法	计算复杂度
MUSIC算法	O=(2L+1)²K+(2L+1)³+ 360(2L+2)(2L+1-P)
ESPRIT算法	O=(2L+1)²K+(2L+1)³+ 6P²(2L-1)+12P³
PM算法	O=(2L+1)²K+(2L+1)²P+ P²(2L+1)+360(2L+2)(2L+1-P)
OAM-PM算法	O=(2L+1)²K+(2L+1)²P+ P²(2L+1)+6P²(2L-1)+12P³

图7 不同模式数的计算复杂度

Fig.7 Computational complexity of different mode numbers

图8 不同快拍数的计算复杂度

Fig.8 Computational complexity of different snapshots

图9 均方根误差与信噪比关系图

Fig.9 Dependence of root mean square error on signal-to-noise ratio

图10 均方根误差与快拍数关系图

Fig.10 Dependence of root mean square error on snapshots

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