Circularly polarized annual ring antenna perturbed by asymmetrical defected ground structures for improved gain

A novel perturbing methodology using asymmetrical defected ground structure (DGS) is proposed for a circularly polarized (CP) annual ring antenna with improved antenna gain. By loading two fairs of half dumbbell-shaped DGS at four diagonal corners of the ring radiator, the orthogonally polarized modes are controlled. Simulated and measured results show that the proposed antenna demonstrates good CP radiations at the resonant frequency. (C) 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2994-2996, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26420