A Novel Sparse MIMO Array with Higher Uniform DOF and Sensor Separation

In this paper, a novel sparse multiple-input and multiple-output (MIMO) array (SMA) is proposed with closed-form expression. The proposed SMA is devised using the difference-coarray of the sum-coarray concept and the uniform linear array (ULA) fitting (UF) principle. More specifically, the transmitting and receiving arrays of the proposed SMA are sparse arrays designed via the UF principle. Compared with the existing SMAs, the proposed SMA has augmented uniform degrees of freedom (uDOF) and sensor separation. Numerical simulations verify the good capacity of the proposed SMA in terms of uDOF, mutual coupling, and direction finding accuracy.