A Broadband Dual Circularly Polarized Transmitarray With Independent Beam Control

In this letter, a broadband dual-circularly polarized transmitarray (dual-CP TA) with independent beam control is reported. Based on Huygens’ metasurface elements, a spin-decoupled dual-CP phase design method is employed to achieve independent beam control. The transmission efficiency and phase shift range are enhanced by cascading multiple layers. Four distinct element sizes provide 180° of dynamic phase coverage, and a 90° rotation of the element enables a 180° phase reversal. A 2 × 2 magneto-electric (ME) dipole antenna is used as the feed, reducing the antenna profile to 4.5${{\lambda }_0}$. At 20 GHz, the measured gains of left-handed CP wave and right-handed CP wave are 21.5 dBic and 21.2 dBic, with peak aperture efficiencies of 23.5% and 22%, respectively. The 2 dB gain bandwidth (BW) and 2 dB axial ratio BW are superior to 13.9% and 11.3%, respectively.