Single-Pixel Scanning Near-Field Imaging With Subwavelength Resolution Using Sharp Focusing Mikaelian Lens

Obtaining sharp focusing with high resolution is of significant importance to microwave and millimeter-wave imaging and sensing. Here, we propose an all-dielectric surface focusing Mikaelian lens operating at the $X$ - and Ka -band, respectively, with the high-resolution focusing of theoretical full-width half-maximum (FWHM) around $0.45\lambda $ for the single-pixel scanning microwave and millimeter-wave imaging. Benefitting from easily accessible 3-D printing, the designed lens prototype with perforation and infill structure can be fabricated at a very low cost. Moreover, numerical simulations and the spatial resolution imaging experimental results demonstrate that the proposed lens prototype exhibits excellent imaging performance with a subwavelength resolution of $\sim 0.5\lambda $ while maintaining broadband behavior, revealing great potential for high-resolution microwave and millimeter-wave imaging applications.