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Abstract-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 ) and superb uniformity among the elements ( 0 1 dB and 0 5 ) 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.

Abstract-A generalized conversion matrix (GCM) and numerical analysis are used to study the distortions suffered by a linear frequency-modulated radio frequency (RF) pulse while propagating through photonic links to be used in wideband phased arrays. The analysis shows the effects of dispersion of all orders, coherent crosstalk and nonlinearity of the optical components on the RF pulse, and the high performance needed to achieve acceptable RF performance of the temporal (impulse) response. The effects of the electrical-to-optical (E/O) and optical-to-electrical (O/E) conversions are also considered. Using the GCM, the optical amplitude and phase fluctuations are converted into their RF counterparts, thereby reducing the optical problem into the wellunderstood RF domain. A photonic wavelength-controlled true delay device is experimentally shown to achieve good RF performance over a 4-GHz bandwidth, with predicted sidelobe levels below 30 dB.

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