الفهرس 
Beamformers…Only 14 pages are availabe for public view
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Abstract
A useful solution for efficient spectral utilization is the exploitation of the spatial domain. It requires the employment of smart antennas which can be used as beamformers. Until recently, research on the beamformers has been restricted mainly to narrowband wireless systems. In order to overcome the shortfalls of narrowband beamformers, several wideband and adaptive wideband beamforming methods have been proposed recently. Smart antennas can also be used in the direction of arrival estimation of signal sources using different signal processing methods. These methods are valid only for narrowband signals where time delay can be approximated as a phase shift. For wideband signals, a steering vector transformation technique is used first before applying any direction of arrival estimation methods. In the present work, the steering vector transformation technique is applied to the conventional frequency domain beamformer in order to enhance the frequency invariance of the mainlobe pattern. It is observed that, as the array size increases or the inter element spacing decreases, the proposed beamformer still has a better frequency invariant property of the mainlobe pattern than the conventional beamformer. Finally, using windows, a better frequency invariant property of the mainlobe pattern is obtained by the proposed beamformer than the conventional one.