Generation of Circular Airy OAM Beam by Conformal Holographic Impedance Metasurface

In this paper, a conformal tensor holographic impedance metasurface (CTHIM) is presented to generate lefthanded circular polarized (LHCP) circular Airy orbital angular momentum (OAM) beams. The CTHIM operates at a frequency of 32 GHz, generating a circular Airy OAM beam with mode number of +1 order, and deflection angle of $\left(\theta=30^{\circ}, \varphi=0^{\circ}\right)$. The Blackman window function is used for the optimal design of the modulation depth. To the knowledge of the authors, there is no literature on the generation of circular Airy beams using CTHIM. The nondiffractive distance (ND) of the Airy OAM beam is $54 \lambda$, the self-focusing distance is $\mathbf{4 5 0} \mathrm{mm},+1$ order OAM mode purity is $\mathbf{9 2. 2} \%$, and the conversion efficiency is $\mathbf{4 6. 6 \%}$. The metasurface has a radius of 65 mm and an area of $\pi \times(6.9 \lambda)^{2}$. The conformal structure can fit the surface of columnar devices, which is more in line with the actual needs in the fields of communication, radar, and medical treatment.