| This thesis was performed by first understanding the concept of DoA estimation and realizing its importance and applications. Second, DoA estimation techniques, which are not few and vary in principle and applications, were reviewed in order to find the most suitable technique to use in this thesis. The target is to find a DoA technique that is simple to construct to illustrate the effect of mutual coupling and array antenna element selection on the DoA estimation process, and at the same time, to be a technique from which the obtained results could be generalized to more specific cases rather than one or two cases. The Maximum Likelihood Method was found to be the most suitable DoA technique. Third, the MLM was implemented using both, omni-directional elements and point sources as the array antenna elements. Fourth, NEC2 was introduced, its theoretical and principal of operation were explained. Also mutual coupling between the array elements was introduced as it affects the over all performance of the array structure in DoA estimation. Finally, a NEC2-Matlab interface was implemented to produce Mean Square Error graphs for different scenarios using the MLM and lambda/2 dipole antennas as the array elements and then lambda/2 dipole antennas above perfectly conducting ground plane. This change of elements in the array structure produced a significant enhancement in the DoA performance. Another approach that was also tested was changing the spacing between the array elements. This approach, under certain conditions, also showed a significant enhancement in the DoA estimation performance. |
