Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 146-147).

Conventional beamformers can be sensitive to mismatches between presumed and actual steering vectors of the signal-of-interest. A recently proposed class of robust beamformers aim to counteract this problem by using a non-attenuation constraint inside a single hypersphere centered at the presumed steering vector of the signal-of-interest. In an effort to strike a balance between robustness to steering vector error and interference-plus-noise suppression, we propose in this manuscript to use multiple concentric hyperspheres instead of one with different degrees of protection in each. We derive several useful properties of this multiply constrained beamformer and use numerical simulations to show that using two constraints yields improved signal-to-interference-plus-noise-ratio compared to one constraint in certain scenarios, particularly at a large input signal-to-noise-ratio. / The manuscript also includes an overview of conventional beamforming, the mismatch problem and previously proposed robust beamformers.

Thesis (M.E. 1971) from the Faculty of Engineering, University of Adelaide.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 135-137). Also available via the Internet.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 161-164).

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.

No description available.

Thesis (Ph.D.)--City University of Hong Kong, 2006. / "Submitted to Department of Electronic Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy" Includes bibliographical references (leaves 179-189)

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 174-175).

No description available.