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Title:Antenna element pattern reconfigurability in adaptive arrays
Author(s):Roach, Tyrone L.
Director of Research:Bernhard, Jennifer T.
Doctoral Committee Chair(s):Bernhard, Jennifer T.
Doctoral Committee Member(s):Cangellaris, Andreas C.; Schutt-Ainé, José E.; Oelze, Michael L.
Department / Program:Electrical & Computer Eng
Discipline:Electrical & Computer Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):multifunctional phased arrays
pattern variability
small adaptive arrays
radiation reconfigurable antennas
least mean square
null reconfigurability
Abstract:This dissertation investigates the functional benefits of utilizing radiation reconfigurable antennas in an adaptive array setting. The work centers on arrays composed of a small number of widely spaced elements. Such array configurations (1) mitigate the effects of mutual coupling between reconfigurable elements, thereby maximizing their individual performance potential, and (2) establish a platform for applications seeking portability and requiring a small system package as a design priority. One aspect of the research extends the early work of R.T. Compton Jr. and others in adaptive arrays by going beyond utilizing ideal, traditional, fixed-pattern antenna element patterns to include element patterns more relevant to pattern reconfigurable antennas. The results demonstrate that a practical pattern reconfigurable element can produce results comparable to that of the ideal element and maintain good adaptive array performance in terms of output signal-to-interference-noise ratio (SINR). Detailed analysis presents the limitations of Compton’s approach, which only specifies the requirements of the additional reconfigurable element based on the original set of two elements in the array. This research overcomes these limitations by fully leveraging the capabilities of the available pattern reconfigurability. Therefore, using a systematic approach, the work integrates pattern variability directly into two different optimization routines, a convex and least mean square technique. The methodology expands the available solutions by allowing the algorithm itself to determine the range of possible antennas states. The developed framework incorporates an antenna pattern model with beam tilting characteristics, which is incorporated in each routine. The advantages and disadvantages of both methods are discussed in terms of pattern variability implementation through a number of adaptive array scenarios. Results establish a roadmap for the specification of pattern reconfigurable antenna capability that promises to improve small adaptive array performance. In particular, the research shows that designers should focus on an element’s null steering capability rather than beam tilting capacity.
Issue Date:2010-05-14
Rights Information:Copyright 2010 Tyrone L. Roach
Date Available in IDEALS:2010-05-14
Date Deposited:May 2010

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