Dual-Resonance SIW-Based Reflectarray Unit Cell for Broadband Applications

A novel concept is introduced for a reflectarray unit cell based on substrate integrated waveguide (SIW) technology in Ku band. Two half-mode resonances are excited inside a slot-coupled single-layer SIW cavity. The two are independently tunable through two tuning vias, allowing for simple broadband design optimizations. This structure achieves more than a full cycle of phase shifting from 15.5 GHz to 22 GHz, for a 35% bandwidth. The use of a resonant cavity also introduces excellent angular stability to the cell response across the band.