Beam Scanning for Dual-Polarized Antenna With Active Reflection Metasurface

In this letter, a dual-polarized antenna with steerable beam is presented. The antenna consists of an active reflection metasurface and a cross dipole antenna. The beam scanning of the antenna is obtained by tuning the capacitance of the varactor diodes mounted on the active reflection metasurface cell. A reflection phase covering 300° can be obtained by tuning the capacitance value. The air layer in the middle of the reflection unit makes the reflection phase curve flat and achieve a stable phase difference over a wide band. Moreover, the cross-shaped structure of the reflection unit can manipulate the reflection phase of the electromagnetic waves with two polarizations. Therefore, the dual-polarized antenna can maintain good radiation performance and port isolation while the beam is deflected. The simulated radiation efficiency is higher than 88%. The measured results demonstrate that the beam-steering range is ±20°, short for voltage standing wave ratio (VSWR) is less than 1.7 and the port isolation is greater than 20 dB in the frequency range of 3.3–3.6 GHz.