Full dimensional mm-Wave beamforming is essential for the successful deployment of 5G. Towards this end, in this work, a fully planar true-time-delay multibeam network based on the Blass matrix topology, is presented, as an alternative to bulky lens-based beamformers. To our knowledge, this is the first planar true-time-delay 2D beamformer. As a proof of concept a 2 × 2 Blass matrix design is designed to operate at 24-31 GHz bandwidth. Our proposed design has a footprint of 4.5λ0×3.6λ0, whereas state-of-the-art true-time-delay 2D beamformers occupy space of 14λ0 × 4λ0 × 4λ0.
