Wideband Polarization-Insensitive Reconfigurable Reflectarray Antenna Based on Identically Spin-Locked Metasurface

A novel concept of wideband polarization-insensitive reconfigurable reflectarray antenna (RRA) is proposed by using an identically spin-locked metasurface. Different from the geometric phase (φ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>L</i></sub> = −φ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>R</i></sub>), identically spin-locked phase that is the same for left- and right-handed circular polarization (LCP & RCP) states (φ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>L</i></sub> = φ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>R</i></sub>), which can be realized by decoupling the dual-helicity. Since any polarization wave is a superposition of LCP and RCP waves, the same phase can be imparted to any polarization wave under the condition of identically spin-locked phase. The 1-bit reflected phase for any incident wave can be controlled dynamically by altering the orientation state of each element with 0° or 90° through micromotors. For demonstration and possible applications, a prototype composed of 30 × 30 elements is fabricated and measured, which is applied to beam scanning. Numerical and experimental results illustrate that our RRA can work in dual linear polarization (LP) and dual CP states, reaching a wide-angle beam scanning up to ±40°. The maximum measured gains in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i>-LP and RCP channel are 26.4 dB at 15 GHz and 25.9 dB at 15.2 GHz, respectively, and a 3 dB gain bandwidth more than 27%. These findings hold significant promise for the advancement of versatile beam scanning, which provides promising applications in wireless communication and radar systems.