Low-Sidelobe Phased-Array-Fed Cylindrical-Reflector Antenna

A phased-array-fed cylindrical-reflector antenna with superquadric projected aperture has been designed to afford the ability to scan the beam over a wide angular range without having to resort to a large focal-to-diameter ratio and without incurring excessively strong sidelobes. The standard of comparison for this antenna is a paraboloidal-reflector antenna, which offers limited scanning capability at a low value of F/D (where F is focal length and D is diameter). The scanning capability of a paraboloidal-reflector antenna is improved by increasing F/D, but for a given large D, this entails an increase in F and thus in the size of the antenna structure needed to support a feed element at the focal point. The present phased-array-fed cylindrical-reflector antenna would be compact (F/D of only about 0.4, where the cross section of the cylindrical reflector, in x z plane, is a parabola with diameter, D), yet would feature relatively low sidelobes at beam-scan angles as large as 16° off the geometric boresight axis in the plane that contains the cylindrical axis.