A 1-Bit Coding Reflective Metasurface for Beam Steering Along Both the Cardinal Planes Using Dual-Polarized Incident Waves

In this paper, a 1-bit coding reflective metasurface is proposed. It can steer the dual-polarized incident electromagnetic waves towards the desired directions along both the xz- and yz- cardinal planes. The unit cell of the coding metasurface consists of a slotted cross-dipole on the top layer. It has a ground plane sandwiched in-between two RT5870 dielectric layers. Two positive-intrinsic-negative (PIN) switches are attached on the top layer in the x- and y- directions to manipulate the TM and TE polarized incidences, respectively. With the switching between the ON and OFF states of the PIN diodes along x- and y-directions, identical phase responses are achieved for TM and TE polarizations, respectively. A phase difference of 180° is achieved at 13.2 GHz between the ON and OFF states for both polarizations. An array of 18×18 such unit elements are used to construct the metasurface with different coding patterns. Using the spectral domain analysis and convolution property of the Fourier transform, the coding patterns are determined for the desired angle of beam steering. A good agreement is observed between the theoretically calculated and full-wave simulated far-field radiation patterns.