الفهرس | Only 14 pages are availabe for public view |
Abstract The present thesis aims to design an adaptive antenna array which is capable of estimating the direction of arrival (DOA) of multiple incoming signals during reception. The adaptive property of the antenna described its ability to automatically orient the beam during transmission to the directions detected during the reception. The estimation of the direction of arrival of multiple signals is achieved under the assumption of noisy environment. The use of adaptive antenna arrays improves the capacity of wireless systems and it have many applications in satellite, and radar and providing improved safety through position location capabilities. Such arrays can be used for interference rejection through spatial filtering, and determine position location through direction finding measurements. The thesis provides a review of the techniques and concepts for direction-of-arrival estimation and proposes a new technique, which depends on the correlation between the matrix representing the signals at the receiving array elements and the steering matrix of the same array. The proposed technique makes use of the locations of the Peaks of the correlation at matched angles of arrival therefore this technique is called ”PCAMA”, which stands for ”Peaks of Correlation At Matched Angles”. The present thesis introduces a practical two-dimensional planar antenna array whose element is a crossed-dipole turnstile composed of two perpendicular dipoles fed in phase quadrature, i.e. 90° phase shift, to produce circular polarization. The proposed antenna array is shown to act in a very similar manner to the hypothetical array composed of point source elements. The steering matrix for the proposed antenna array is obtained through electromagnetic simulation. The obtained results show good efficiency of the proposed antenna array together with the applied processing technique. The accuracy of the obtained results for the angles representing the DOA of each signal is shown to be dependent on the Signal-to-Noise Ratio (SNR). The proposed processing algorithm and |