The Ray Insertion Method (RIM) is a novel approach for controlling the propagation path of electromagnetic waves. This method enables the design of desired starting and ending points, as well as incident and exiting angles.By utilizing numerical solutions of the eikonal equation, the refractive index distribution between component endpoints is determined. Additionally, the method employs the periodic properties of metasurfaces. Patches of appropriate sizes are used based on different refractive index requirements. Subsequently, according to the Gradient Refractive Index (GRIN) distribution designed through RIM, these patches are distributed on a grounded dielectric substrate. This design technique is validated through simulations, demonstrating that the lens bends along the specified path and achieves the desired invisibility area and shape. Metasurfaces of the manufactured metamaterial cloaking lens also align with the expected results. 

▶ Tien-Chen Yang, Yi-Kai Chen, and Malcolm Ng Mou Kehn, "Metasurface cloaking lens designed by the ray insertion method," in IEEE Antennas and Wireless Propagation Letters, vol. 22, no. 6, pp. 1471-1475, June 2023. (Link)
▶ Jen-Yung Li and Malcolm Ng Mou Kehn, "The 90° rotating Eaton lens synthesized by metasurfaces," in IEEE Antennas and Wireless Propagation Letters , vol. 17, no. 7, pp. 1247-1251, July 2018. (Link)
▶ Jiun-Wen Yang, Wei-Yu Lai, Hai-Cheng Chou, and Malcolm Ng Mou Kehn, "Compact Mikaelian lens synthesized by metasurfaces," in IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 3, pp. 397-400, March 2018. (Link)