M.Ing. (Electrical & Electronic Engineering) / A new method is presented for significantly reducing the large number of complex computations associated with beamforming, -steering and adaption in large antenna arrays. The structure is based on linear interpolation over (L +1) array elements implying that the (L -1) antenna or sensor signals in-between are added with simple weights to the neighbouring antenna signals for beamforming and/or steering. If L is chosen to be a power of two, these simple weights become h t, i, etc. or multiples thereof. It is easily implemented on a microcomputer with shift operations and can be performed in reduced time compared to byte and word multiplications. The maximum value of L that can be used increases with decreasing mainlobe width. A problem that arises when performing beam steering on such an array is that the level of the sidelobes-more specifically the suppressed mainlobe images which are the result of the interpolation process-increase with increasing steering angle. The maximum.steering angle is determined by the constraints placed on the sidelobe level. To be able to steer wider than the maximum steering angle, it becomes necessary to apply complex interpolation to the array. Complex interpolation refers to the steering of the interpolator beam. The interpolation process reduces the number of weights. This results in a significant reduction of the number of computations associated with adaptive beamforming algorithms.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:11310 |
| Date | 02 June 2014 |
| Creators | Van Wyk, Michael Antonie |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Johannesburg |
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