High aperture efficiency symmetric reflector antennas with up to 60 deg field of view
Abstract
A microwave singlereflector scanning antenna derived from an ellipse (rather than the usual parabola) which gives a much greater field of view is presented. This reflector combines reasonable scanning in one plane with good focusing in the other, and its scanning ability is superior to the torus and other single reflectors because it has much greater aperture efficiency and is thus smaller while having the same performance. The reflector surface is derived in two steps: a fourthorder even polynomial profile curve in the scan plane is found using least squares to minimize the scanned ray errors; then even polynomial terms in x and y that minimize astigmatism for both the unscanned and maximally scanned beams are added to form the threedimensional surface. Numerical simulations of radiation patterns for a variety of antenna diameter and fieldofview cases give excellent results. The 60 deg scan case with 30lambdadiameter aperture has only 0.2dB peak gain deviation from ideal and first sidelobe levels below 14 dB down from peak gain. The 17 deg, 500lambda case has only 0.8dB gain variation and 14 to 11 dB sidelobe levels for approximately +/68 beamwidths of scan, with focal length to aperture diameter ratio equal to about one.
 Publication:

IEEE Transactions on Antennas and Propagation
 Pub Date:
 March 1991
 DOI:
 10.1109/8.76331
 Bibcode:
 1991ITAP...39..336R
 Keywords:

 Antenna Design;
 Microwave Antennas;
 Reflector Antennas;
 Antenna Feeds;
 Antenna Radiation Patterns;
 Apertures;
 Phase Error;
 Ray Tracing;
 Communications and Radar