Broadband Adjustable Gain Bidirectional Radiation Antenna Based on Polarization Rotating Metasurface

We present a bidirectional radiation antenna (BRA) with adjustable gain and broadband features. In the design of BRA, a novel antenna scheme combining transmitarray (TA) and folded transmitarray (FTA) is proposed, which can simultaneously switch the function mode of TA and FTA along forward and backward directions on the basis of the rotation of feed antenna, leading to the ability of reconfigurable gains of the bidirectional pencil beams. To build the proposed antenna scheme, two transmitted polarization rotating metasurface (TPRM) are orthogonally placed at the top and bottom side of a feed antenna with certain distance, respectively, whose function is to transmit and focus the incident electromagnetic wave. A protype is designed and simulated, in which a three-layer broadband polarization rotating unit cell is developed to achieve 360° phase shift for phase compensation. The numerical and measured results indicate that the proposed design is capable of showing bidirectional pencil beams simultaneously.