Generalized range migration algorithm for synthetic aperture radar image reconstruction of metasurface antenna measurements

摘要

Waveguide-fed dynamic metasurface antennas (DMAs) can be used in a variety of synthetic aperture radar (SAR) modalities for microwave and millimeter-wave imaging. The DMA consists of an electrically large array of resonant, dynamically reconfigurable metamaterial radiators, each excited by the fields of a guided wave. A given metamaterial element can be modeled as a polarizable dipole, with polarizability that equates to a complex weighting factor in the context of antenna array calculations. The DMA produces a sequence of diverse radiation patterns as a function of the weights, which can be rapidly varied by external control. The unconventional radiation patterns of the DMA, however, introduce added computational complexity for traditional SAR processing algorithms. One SAR reconstruction approach that has successfully been adapted for the static (motionless) DMA is the range migration algorithm (RMA). Here, we extend the RMA to scenarios in which the DMA is physically translated in one or two dimensions, deriving the RMA for each case and providing experimental demonstrations using a fabricated microstrip-based DMA. Excellent reconstruction quality is observed in all cases, verifying the efficacy of the proposed algorithms and demonstrating the imaging capabilities of the DMA in the synthetic aperture context. The combination of the DMA platform with efficient reconstruction algorithms can find applications in fields such as Earth observation, security screening, and autonomous vehicle navigation. (C) 2017 Optical Society of America