Abstract
Spherical reflectors have been used as wideβangle scanning antennas due to the unique geometric properties of the sphere. The inherent spherical aberration, however, causes considerable performance degradation. This article presents a novel subβreflectarray compensating technique to correct it. A microstrip reflectarray is a planar, inexpensive, passive device with unique capabilities of controlling reflection phases. By exploiting this feasible property, it is employed as an auxiliary phase corrector, and the phase errors caused by spherical aberration are compensated. Two examples, a 35βm spherical reflector antenna at Kaβband and a 1.5βm breadboard spherical reflector, are presented, and simulation results show great performance improvement for both no scan and large scan cases. Because of the difficulty in measuring large reflector antennas at UCLA, it is part of future plan to collaborate with other institutions for the verification of the concept. However, we believe that the simulation results generated in this article should provide acceptable performance prediction of the proposed antenna design. Β© 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 577β582, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24088