Submicrosecond Scan-Angle Switching Photonic Beamformer With Flat RF Response in the C and X Bands

A wideband (>10 GHz) beamformer, based on a photonic true-time-delay, with submicrosecond scan-angle switching is reported. The smooth microwave transmission (ripples <0.5 dB and <3 degrees) and superb uniformity among the elements (<0.1 dB and <0.5 degrees) are then used for the processing of 1 GHz-wide linear frequency modulation (LFM) signals in both the C and X bands with excellent performance. This performance is also maintained under dynamic operation, where a fast tunable laser is employed to provide <300 ns wavelength-controlled angle scanning. Based on these characteristics, an optimized architecture, where a photonic beamformer feeds a series of classical subarrays, can offer high performance in both the time and spatial domains for large, wideband phased-array antennas, with wide scan angles.