Abstract
—This paper presents a unit cell with high efficiency for simultaneous transmission and reflection (STAR) surface operating at millimeter wave frequencies. Applying two perpendicular metallic gratings in the top and bottom of a dual-C shaped resonator, the unit cells can simultaneously control amplitude and phase of reflected and transmitted waves by adjusting the geometrical parameters. This structure can be leveraged to realize full-space electromagnetic manipulation in a simple way for potential applications in mutlifunctional devices.