Dual Band Shared Aperture Polarization Converting Reflectarray for Independent Beamforming in C and X Bands

This paper presents a dual band shared aperture reflectarray for independently controlling the direction of reflected beams in C and X bands. It is based on a linear polarization converting unit cell which can independently tune the reflection phase responses in both the bands by mirroring the orientations of two concentric split ring resonators (SRRs). The 1-bit reflectarray is designed by arranging the binary mirrored states of the unit cell components creating distinct surface phase distribution profiles in both the frequency bands. Since each component of the unit cell provides independent phase tunability, the planar phase distributions in both the frequency bands can be configured independently to convert incident spherical waves to collimated beams in the desired directions. Two reflectarrays are designed using the proposed unit cell, one for broadside reflection in both the bands while the other for demonstrating the independent beamforming ability at different frequencies.