Off-axis beaming from subwavelength apertures

Photonic crystal waveguides and metallic subwavelength apertures are promising tools for light manipulation. It is possible to obtain enhanced directional beams by using these structures via coupling to surface waves. In addition, these apertures can be designed to steer such directional beams by introducing asymmetrical gratings on the output surface. In the present paper, we report directional yet off-axis beaming from subwavelength apertures at microwave frequencies. The full width at half maximum of the beam is 10° while the beaming angle is 15°. Our results show that it is possible to steer the beam by the appropriate modification of the output surface.