Design of a Direction Independent Uniform Scan Array

Yoonjae Lee and Suman Ganguly

Abstract:	We present non-planar phased-array designs for GPS applications. They can be easily adapted for accommodating new frequencies such as for beacon receivers, cellular phones, Galileo and so on. In a normal planar array, the spot size varies with the angle of beam direction. The narrowest beam width is generally achieved for the direction normal to the surface of the two-dimensional array. For signals arriving from low elevation angles near horizon, the localization of those signals require increased directivity at lower elevation angles, thus conventional array designs must be modified to accommodate such needs. The designed antenna is useful for anti-jamming applications providing capabilities for nulling towards interfering signals with arbitrary incident angles and maintaining enhanced reception of low angle GPS satellites signals. It is also useful for detection and characterization of signals coming from low elevation angles such as multipath. One of the problems in tightly packed arrays is the mutual coupling. It has adverse effects changing the antenna characteristics such as impedance, radiation pattern, and polarization. The designed antenna is optimized using the genetic algorithm (GA) to further enhance the performance. We present the antenna characteristics in terms of max. directivity, max. side lobe levels, beam width, null depth, etc. The designed antenna offers improved capabilities for anti-jamming and characterization of interference signals by achieving an angle-independent scan characteristic.
Published in:	Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005) September 13 - 16, 2005 Long Beach Convention Center Long Beach, CA
Pages:	667 - 678
Cite this article:	Lee, Yoonjae, Ganguly, Suman, "Design of a Direction Independent Uniform Scan Array," Proceedings of the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2005), Long Beach, CA, September 2005, pp. 667-678.
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