College of Electronic Science;
National University of Defense Technology;
Changsha 410073;
China;
College of Electronic Countermeasure;
National University of Defense Technology;
Hefei 230037;
China;
College of Computer and Information Technology;
China Three Gorges University;
Yichang 443002;
China;
high-order extended coprime array(HoECA); direction of arrival(DOA); degree of freedom(DOF); mutual coupling;