摘要：Nonuniform linear arrays,such as coprime array and nested array,have received great attentions because of the increased degrees of freedom(DOFs)and weakened mutual *** this paper,inspired by the existing coprime array,we propose a high-order extended coprime array(HoECA)for improved direction of arrival(DOA)*** first derive the closed-form expressions for the range of consecutive ***,by changing the inter-element spacing of a uniform linear array(ULA),three cases are proposed and *** is indicated that the HoECA can obtain the largest number of consecutive lags when the spacing takes the maximum ***,by comparing it with the other sparse arrays,the optimized HoECA enjoys a larger number of consecutive lags with mitigating mutual *** results are shown to evaluate the superiority of HoECA over the others in terms of DOF,mutual coupling leakage and estimation accuracy.