A SiN antenna based on grating–waveguide–grating structure for unidirectional and uniform emission

High-directionality antennas can efficiently avoid blind spots in the field of view. And a uniform emission antenna can improve the  near-field distribution of the antenna, increase the effective aperture of the antenna, and thereby reduce the divergence angle. In this manuscript, a SiN antenna of highly upward emission directionality and uniform emission based on the grating–waveguide–grating sandwich  structure is designed. For the antenna, it has a flat near-field and a side mode suppression ratio of less than 0.2 from 1540 nm to 1620 nm. The length of the antenna is 500μm and the divergence angle is 0.17° at 1550 nm. The beam steering range  is 5.54° from 1540 nm to 1620 nm and the upward directionality is over 80%. The highest upward directionality is about 92% at 1540 nm. These indicate that the proposed antenna can also be applied to LiDAR and  so on.