Spatial-spectrum estimation and filtering of radio frequency arrays via elemental photonic up-conversion and coherent optical processing
Date
2017
Authors
Journal Title
Journal ISSN
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Publisher
University of Delaware
Abstract
A method for imaging Radio-frequency (RF) side-bands about an optical carrier
signal, previously devised for passive, non-coherent, imaging of millimeter wave radiation
is furthered for use in coherent reception of Radio-frequency signals. Theoretical
formulation of a novel photonic beam-space beam-former is presented along with relationships
to traditional beam-space array theory. The photonic beam-forming system
requires each element of a Radio-Frequency (RF) array be optically up-converted to a
laser carrier frequency and fed through a photonic processing system, where the output
beam-space is sampled using an array of photo-detectors (or a commercial camera).
Specic contributions of this work allow for a more power ecient optical system,
amplitude calibration of the optical chain, arbitrary apodization (or tapering) of the
output beam-space and application of the receiver system to multiple simultaneous
domains (e.g. active sensing and communications in one receive array). Furthermore,
a novel adaptive weighting approach is presented that utilizes outputs from both a
commercial camera device and an array of high-speed photo-detectors to enable array
adaptivity that is shown to be of low-latency when compared to existing techniques.
Several experiments are performed using prototype hardware to characterize the system,
component and algorithm-level performance enabling more capable designs within
future work.
Description
Keywords
Applied sciences, Array, Covariance matrix, Photonics, Spatial frequency