Research On Continuous Aperture Extension Based On MIMO Array

Using its own unique transmitting and receiving mechanism,Multiple Input and Multiple Output(MIMO)array could virtual out a sum co-array,which has more elements than the actual one could be,by separating itself to a transmitting array and receiving array.Compared with the traditional uniform linear array,MIMO array has a huge advantage in degree of freedoms(Do F)and array successive aperture,under the case of having same antenna elements.Combining with the Direction-of-Arrival(DOA)algorithm,MIMO array has already become the hotspots in active sounding application,such as radar or active sonar.So,in this thesis,based on the MIMO array,some improvements and deep research has been done.The details are as follows.1.Combined with the co-prime array,a special co-prime MIMO structure has been given,and the array structure of sum co-array based on it has been analyze.Then,in order to fill the holes in sum co-array,a hole filling technique has been proposed.Uniting the advantage of MIMO array---active detection and the special array structure of sum co-array of co-prime MIMO array which been mentioned above,the receiving array of co-prime MIMO array could receive a series of data vectors with different frequency,by setting a series of specific extra frequencies in the probe wave.Then,some specific elements of data vector with different frequency will be selected as the elements to fill the holes of sum co-array of coprime MIMO array.Compare with the traditional algorithm that one extra frequency to one hole,this hole filling technique could achieve one extra frequency fills more than one hole in one operation,which mean that this new technique can fill holes much more efficiently.2.Combined with the Nested array,an algorithm based on dual frequencies is proposed here to increase the Do F of DCSC of nested MIMO array.This method utilizes the successive elements of sum co-array of nested MIMO array,forming a bigger nested array by combined the data vectors obtained from different frequency.Compared with the traditional nested MIMO array that using only one frequency,using dual frequency on nested MIMO array not only could maintain a proper array size,but also increase the Do F of DCSC of nested MIMO array largely.