Beam-Deflection Short Backfire Antenna Using Phase-Modulated Metasurface

Abstract

This communication presents a beam-deflection short backfire antenna (BD-SBA). The proposed BD-SBA differs from the conventional SBA in that the main reflector of the BD-SBA is a phase-modulated metasurface instead of a perfect electric conductor (PEC). The phase-modulated metasurface consists of 15 columns of unit cells which are designed to change the phase of the reflected waves. Therefore, the beam of the BD-SBA can be deflected to a certain angle. First, several BD-SBAs with linear phase-modulated metasurfaces are studied, which indicates that the beam of antennas point at different directions. Second, the BD-SBAs with nonlinear phase-modulated metasurfaces are studied to compare the difference between metasurfaces with linear and nonlinear width variation of patch. The simulated results show that the metasurface with nonlinear variation can obtain better performance than the former. To verify this design method, the BD-SBA with $\Delta \theta = 10^{\circ }$ was fabricated and measured at ${X}$ -band. The overall height of the proposed antenna is 0.35 wavelength at 10 GHz. The measured and simulated results are in good agreement; the measured beam-deflection angle, realized gain, and aperture efficiency are 10°, 14.8 dBi, and 68.3% at the center frequency, respectively. Due to the beam-deflection function, medium-to-high gain characteristics, and low profile, the proposed BD-SBA can be expected to find potential applications in wireless backhauling.