Multi-interaction of surface wave between subwavelength grooves surrounding a single metallic slit

We propose a physical understanding of scattering by subwavelength grooves surrounding a single perfect conductor slit based on the superposition of a cylindrical traveling surface wave and a standing surface wave. The collective reflection coefficient was introduced to handle the multi-interaction of the surface wave between subwavelength grooves, and a slit-grooves focusing structure was designed to demonstrate its validity. In comparison to numerical simulations by the finite difference time domain method, the proposed method proves effective in describing the multi-interaction behavior of a surface wave and in further refining the phase perturbation at the grooves' exits.