Polarization Control of a Metal-Only Transmitarray Unit-Cell

This paper presents a metal-only transmitarray unit-cell exhibiting polarization twisting which allows reducing side lobe level of transmitarray radiation. This dominant capability is proposed and illustrated by two versions of a metal-only unit-cell consisting of four or three identical layers separated by quarter-wavelength spacers at 18.75 GHz (4 mm). The unit-cell is based on C-shaped slot, and the phase variation is achieved by varying the inner radius of the slot. The linear polarization is twisted by gradually rotating consecutively each layer with the same rotation angle.