Broadband Reflective Linear Polarization to Circular Polarization Unit Cells and the Application in Array Design

Abstract

This paper presents a new set of linear polarization to circular polarization (LP-CP) unit cells (UCs) for broadband reflective polarization conversion, and the application in designing broadband CP reflectarray (RA). The LP-CP UCs are composed of different combinations of rectangular loops for different reflective phases. By controlling the ratio of width to length of the rectangular loop, the LP-CP conversion can be realized. By further adjusting the coupling between two rectangular loops, broadband LP-CP conversion can be achieved accordingly. Four phase states of 0 -90°, -180°, and 90° are obtained for the elaborately designed UCs for application in designing CP RA. The measured results show that the final fabricated RA can achieve a wide CP bandwidth of 53% for high gain radiation.