A New Extended Sparse Array for DOA Estimation of Noncircular Signals with Less Mutual Coupling

Recently, in order to increase the degrees of freedom, sparse arrays are widely studied for circular signals. However, there are many applications of non-circular signals in practice, but the characteristics of non-circular signals are rarely considered in array design. A new extended array configuration is designed for non-circular signals in this paper. The configuration is designed by incorporating the extended subarray into the maximum inter-element spacing constraint (MISC) to enlarge the number of continuous virtual array elements in the sum-difference co-array. The closed form expressions of the structure and the number of uniform DOFs are given in this paper. Simulation results show that the proposed geometry provide better accuracy for DOA estimation in the presence of unknown mutual coupling while preserving high degrees of freedom.