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E. J. Polisensky, A.S. Cohen (NRL), L. Kogan (NRAO)
The Long Wavelength Array (LWA) will consist of banks of 256 crossed dipole antennas whose signals are phased together into a single antenna "station" analogous to an individual VLA antenna. The arrangement of dipole elements within the station area is an important design issue as the configuration determines the power pattern of the station. Many different station configurations were studied including grids, spirals, random layouts, and designs that had been sidelobe optimized. The effects of varying station parameters such as the station size, minimum element seperation, number of elements, and positioning errors, were also examined. Configurations were evaluated through the use of metrics that quantify the power pattern, such as the beam efficiency, peak sidelobe level, and maximum effective area. A design minimizing the peak sidelobe level for all pointing angles of the station was recommended as the configuration for the LWA stations. The Long Wavelength Demonstrator Array (LWDA) station will be populated in two test and evaluation stages. The problem of finding an optimum subset for the initial 128 elements was also addressed. Basic research in radio astronomy at the Naval Research Laboratory is supported by the Office of Naval Research.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.