Design of a Broadband Flat Metasurface Lens by Using One-Dimensional Meander Microstrip-Line Structures

We design a broadband flat metasurface lens whose thickness is much thinner than the wavelength. The concept with one-dimensional (1-D) transmission-line model is recalled and 1-D meander microstrip-line structures are used for the design. Determining the specification of the lens, the line length is calculated based on the design formula. The eigenfrequency analysis is carried out to modify the error of electrical length from the theoretical value, and the line length is optimized. A metasurface lens is constituted with the structures and full-wave simulations are performed to confirm the broadband operation. It is seen from the results that the designed lens can make a focus at any frequency.