Circularly Polarized Folded Reflectarray Antenna

This paper presents the analysis and design of an integrated low -profile circularly-polarized folded reflectarray antenna (NRA) for wireless communication applications in the ku band. The proposed FRA consists of a main reflectarray (MR), a tilted linearly polarized (LP) planar dipole antenna and a transmitarray. The main reflectarray consists of 713 pentagonal patch elements on a grounded dielectric substrate. The reflecting elements are adjusted to produce a 90 phase shift between the reflection coefficients in the two principal planes. On the other hand, the transmitarray consists of conducting circular patches printed on a dielectric slab. The combination of the reflectarray and transmitarray are designed to convert the linearly polarized radiation of the feeding planar dipole antenna to circular polarization. In this work a small focal to diameter ratio (FID) is chosen to be 0.4 to reduce the overall antenna size. This design operates in the band from 11.5 to 12.5 GHz and the results show that the maximum antenna gain 22 dBi and the AR is 1.17 dB at 12 GHz.