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A small hemispherical helical antenna array for two‐dimensional GPS beam‐forming
Author(s) -
Hui H. T.,
Aditya S.,
Mohamed F. Bin S.,
HafiedzUl A. Bin T.
Publication year - 2005
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/2004rs003094
Subject(s) - antenna (radio) , beam (structure) , optics , beam diameter , global positioning system , antenna array , power (physics) , beam waveguide antenna , physics , antenna aperture , acoustics , radiation pattern , telecommunications , computer science , laser , quantum mechanics , laser beams
A small hemispherical helical antenna array with multibeam output for GPS beam‐forming is designed and characterized. A Butler matrix beam‐forming network is designed to provide four spatial beams in a two‐dimensional directional space. The original design of the hemispherical helical antenna elements is modified in order to match it to the system impedance. Our study shows that even after an ∼30° scan from the normal direction, the maximum change in beam width is only 6°, the maximum change in axial ratio is 1.4 dB, and the maximum change in power gain is 1.1 dB. These characteristics indicate that the array can be potentially used for GPS beam‐forming.