Hybrid Photonic True-Time Delay Modules for Quasi-Continuous Steering of 2-D Phased-Array Antennas

Traffic information collecting system based on microwave photonics

“…Fig. 2 shows the structure of a hybrid photonic true-time delay controlled phased-array antenna system [6]. Utilizing two stages of programmable TTD network, the system is able to realize 2-D beam forming with no electronic component.…”

Programmable RF photonic phase shifters based on FD-OP for optically controlled beamforming

“…In recent years, various methods for microwave photonic phase shifter have been proposed, for example, based on true-time-delay elements [4][5][6], homodyne mixing techniques [7,8], vector sum techniques [9,10], and nonlinear effects [11][12][13]. It is difficult for the others techniques [7,[9][10][11][12] to operate multiple independent phase shifters, and so the optically controlled beam forming system is complex.…”

Compact optical true time delay beamformer for a 2D phased array antenna using tunable dispersive elements

“…To realize both azimuth and elevation beam steering, the beamformer for a planar array should be able to control time delays in two independent dimensions. Previously, the 2D beamformer was implemented by two stages of TTD [4][5][6][7], with one stage for azimuth beam steering and the other stage for elevation beam steering. In [4], an array of highly dispersive photonic bandgap fibers with preset lengths are employed as the TTD elements in the first stage, in which the time delays are controlled by adjusting the wavelength of a tunable laser source, and optical waveguide delay lines connected by optical switches serve as the TTD element in the second stage.…”