A symmetric sparse array, termed as the symmetric interantenna spacing constrained array (SISC), is proposed for unambiguous direction-of-arrival (DOA) estimation of mixed near-field and far-field source signals. This SISC array is designed from the perspective of assembling four uniform linear subarrays, while balancing the uniform degree of freedom (uDOF) and array sparseness. The SISC array may involve only one closely spaced antenna pair with a spacing of a quarter of the signal wavelength, while synthesizing a contiguous processing aperture with a large uDOF. The minimum interantenna spacing of SISC can also exceed the quarter of the signal wavelength (without a closely spaced antenna pair), if reducing antenna mutual coupling is preferred. Simulation results are provided to verify the superiority of SISC to the current symmetric sparse arrays, in terms of antenna mutual coupling, uDOF, processing aperture, and DOA estimation accuracy.

中文翻译：

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用于混合近场和远场源信号的 DOA 估计的对称天线间距约束稀疏阵列


提出了一种对称稀疏阵列，称为对称天线间间距约束阵列（SISC），用于混合近场和远场源信号的明确到达方向（DOA）估计。该SISC阵列是从组装四个均匀线性子阵列的角度出发设计的，同时平衡了均匀自由度（uDOF）和阵列稀疏性。 SISC 阵列可能仅涉及一个间距为信号波长四分之一的紧密间隔的天线对，同时合成具有大 uDOF 的连续处理孔径。如果希望减少天线互耦合，SISC 的最小天线间距也可以超过信号波长的四分之一（没有紧密间隔的天线对）。仿真结果验证了SISC相对于当前对称稀疏阵列在天线互耦、uDOF、处理孔径和DOA估计精度方面的优越性。