Integrated waveguide true time delay beamforming system based on an SOI platform for 28  GHz millimeter-wave...

In this paper, we propose an on-chip waveguide beamforming system for a 28 GHz millimeter-wave signal based on silicon-on-insulator (SOI) technology. The system consists of four true time delay (TTD) lines, each of which consists of nine Bragg gratings with different periods. The minimum period of the grating is 312 nm, and the maximum period is 344 nm. By optimizing the position of the Bragg grating in the adjacent TTD lines, a time delay difference can be generated between the adjacent channels. By adjusting the operation wavelength of the optical carrier, the TTD lines can provide 9 different beamforming direction angles from -60^∘ to 60° when the direction angular resolution is 15°. This proposed system has a useful application prospect in the phased array antennas of millimeter-wave communication.