Browsing by Author "Schneider, Garrett J."
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Item Array-Beamspace Mapping for Planar Two-Dimensional Beam-Forming(IEEE Access, 2023-07-21) Beardell, William L.; Murakowski, Janusz; Schneider, Garrett J.; Prather, Dennis W.As sixth-generation (6G) communication systems manifest at carrier frequencies well into the millimeter-wave (mmW) spectrum, the ability of conventional digital beamforming techniques to handle the beam-bandwidth product is increasingly stressed. Microwave photonic beamforming has been presented as a solution to this problem by up-converting a sampled RF field distribution to an optical carrier for analog beam-space processing, but to date has relied upon fiber arrays with the same dimensionality as the RF array, i.e., a two-dimensional RF array requires a two-dimensional fiber array and a three-dimensional optical processor to perform the Fourier transform required for two-dimensional beamforming. To address this problem, we present an approach to photonic mmW beamforming wherein two-dimensional phase information is preserved through a one-dimensional Fourier transform leveraging grating lobes in the array response. This approach carries several benefits, primarily as an enabler for leveraging photonic integrated circuits for RF-photonic beamforming, carrying with it a footprint reduction of more than ten thousand times. Furthermore, beamforming efficiency is increased for sources near the limits of the RF field-of-view; improvements to throughput power in such cases are as much as double. Theory, simulations, and experimental results in the form of images and videos are presented to validate the approach for a nineteen-element hexagonally-distributed phased array.Item Microwave Photonic Direction-Finding Spectrometer(Journal of Lightwave Technology, 2023-05-15) Beardell, William L.; Ryan, Conor J.; Schneider, Garrett J.; Murakowski, Janusz; Prather, Dennis W.In this paper, we propose an architecture wherein the radio-frequency (RF) field at the antenna array is up-converted to an optical carrier and passed through an array of optical fibers, after which an analog Fourier transform is taken in a free-space optical processor. Through the use of multiple temporal dispersion projections, implemented through varied-length optical fiber segments, the locations of RF sources in three-dimensional space spanning angle-of-arrival (AoA) and instantaneous frequency may be determined on a millisecond time scale using commercial computing hardware after detection by a charge-coupled device (CCD) camera. We present a mathematical formulation of the problem, followed by simulated and experimental results showing three-dimensional spatial-spectral localization through the solution to a system of equations brought forth through the use of Fourier optics to process the RF field.Item Ultrawideband Modular RF Frontend Development for Photonically Enabled Imaging Receiver(IEEE Microwave and Wireless Technology Letters, 2024-05-07) Shi, Shouyuan; Wang, Fuquan; Abney, Jeremy; Aranda, Zion D.; Schneider, Garrett J.; Schuetz, Christopher; Harrity, Charles; Shreve, Kevin; Zablocki, Mathew; Dontamsetti, Samhit; Lawrence, Robert; Prather, Dennis W.This letter presents a modular-based RF frontend developed for photonically enabled phased-array systems that are capable of ultrawideband (UWB) operation from microwave to millimeter-wave (mmW) frequencies. The 1×8 modular architecture with integrated antennas, low-noise amplifiers (LNAs), and electrooptic modulators is reconfigurable and scalable to form 2-D phased arrays of any size. The developed phased-array system demonstrates the ability to process multiple wide-bandwidth RF beams simultaneously, yielding unmatched beam-bandwidth product (BBP).