A Wideband Reflectarray Based on Polarization Rotating Unit Cells

Abstract

We present a new wideband single-layer reflectarray based on polarization rotating (PR) unit cells. These PR unit cells convert a linearly polarized incident electromagnetic wave to an orthogonal polarization upon reflection wave. Each unit cell consists of a pair of L-shaped patches and a metallic strip tilted at 45° from the x-axis in the xy plane. By adjusting the dimension of this unit cell, a pair of 90° phase difference unit cells were achieved. And we used these two unit cells and their mirror images to achieve a 2 bit phase shifter, which provides a phase shift of 0°/90°/180°/270° from 11 GHz to 17 GHz. Based on the proposed element, a wideband reflectarray is designed, fabricated and measured. The measured results show that the reflectarray s maximum gain is 25.6 dBi, with a 1 dB gain bandwidth of 30.4 % and an aperture efficiency of 35%, which agree well with the simulated results.