Electrically Coupled Graded Index Metamaterial

We have demonstrated that effective gradient index devices can be fabricated to collimate and steer microwave beams by designing the spatial profile of positive effective permittivity across the slab. Resonant losses in the devices is reduced dramatically by operating at frequency ranges far from the unit cell resonance, and substrate losses is reduced by utilizing low loss material. Using these approaches, we demonstrate large steering angles of up to 22 degrees with only 0.7 dB transmission loss. These pave the way for practical implementation of low-cost microwave beam steering devices using metamaterials.