A multi-beam transmitarray antenna with customized power ratios and quad-polarization capability

Abstract The generation of multi-beam with multi-polarization and customized power ratios remains a challenge in transmitarray antenna (TA) design. To address this problem, a beam overlapping method is proposed in this letter. The polarization diversity of the multi-beam is increased by overlapping a pair of orthogonally polarized beams with specific phase difference. A quantitative relationship is established between the power ratios and the number of overlapping operations, enabling precise control over the beam power. To verify the method, a TA operating at 16 GHz is fabricated and measured. The experimental results demonstrate the TA can simultaneously generate right-hand circularly polarized (RHCP), left-hand circularly polarized (LHCP), Y-polarized (Y-LP) and X-polarized (X-LP) beams. Their power ratios are close to the design goal of 2:2:1:1. The 3 dB axial ratio bandwidths of the RHCP and LHCP beams are 37.5% (12–18 GHz). The proposed TA provides better polarization diversity and power control than traditional multi-beam TAs. The multi-polarization capability mitigates polarization mismatch, while the flexible power distribution facilitates rational allocation of limited transmission resources, which enhances the competitiveness of the proposed TA for multi-mode communication systems.