Metamaterial microwave holographic imaging system

Hunt, John; Gollub, Jonah N.; Driscoll, Tom; Lipworth, Guy; Mrozack, Alex; Reynolds, Matthew S.; Brady, David J.; Smith, David R.

doi:10.1364/josaa.31.002109

Cited by 154 publications

(85 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the metamaterial aperture to function as an imaging system, a forward model must be implemented that describes how objects in the scene scatter the incident field, such that the collection of measurements can be inverted and the scene retrieved. Though more sophisticated models can be developed, for our purposes the first Born approximation provides a sufficient description [17,18]. In this approximation, the field scattered from the target, E sca , is simply related to the incident field, E i , through…”

Section: Metamaterials Imagermentioning

confidence: 99%

Resolution of the Frequency Diverse Metamaterial Aperture Imager

Yurduseven¹,

Imani²,

Odabasi³

et al. 2015

PIER

Self Cite

108

View full text Add to dashboard Cite

Abstract-The resolution of a frequency diverse compressive metamaterial aperture imager is investigated. The aperture consists of a parallel plate waveguide, in which an array of complementary, resonant metamaterial elements is patterned into one of the plates. Microwaves injected into the waveguide leak out through the resonant metamaterial elements, forming a spatially diverse waveform at the scene. As the frequency is scanned, the waveforms change, such that scene information can be encoded onto a set of frequency measurements. The compressive nature of the metamaterial imager enables image reconstruction from a significantly reduced number of measurements. We characterize the resolution of this complex aperture by studying the simulated point spread function (PSF) computed using different image reconstruction techniques. We compare the imaging performance of the system with that expected from synthetic aperture radar (SAR) limits.

show abstract

Section: Metamaterials Imagermentioning

confidence: 99%

Resolution of the Frequency Diverse Metamaterial Aperture Imager

Yurduseven¹,

Imani²,

Odabasi³

et al. 2015

PIER

Self Cite

108

View full text Add to dashboard Cite

show abstract

“…Historically, SAR has been employed from aircraft and satellite systems but the technique has increasingly been applied in cases where the standoff distance is significantly shorter. Holographic imaging systems [32], [56] for security screening [6], [8], [9], [30], [31] and feature-specific imaging [57], [58] are of increasing interest and the dynamic metasurface aperture is posed to make important contributions across the entire field of microwave sensing. …”

Section: Discussionmentioning

confidence: 99%

Experimental Synthetic Aperture Radar With Dynamic Metasurfaces

Sleasman

Boyarsky

Pulido-Mancera

et al. 2017

IEEE Trans. Antennas Propagat.

Self Cite

View full text Add to dashboard Cite

Abstract-We investigate the use of a dynamic metasurface as the transmitting antenna for a synthetic aperture radar (SAR) imaging system. The dynamic metasurface consists of a onedimensional microstrip waveguide with complementary electric resonator (cELC) elements patterned into the upper conductor. Integrated into each of the cELCs are two diodes that can be used to shift each cELC resonance out of band with an applied voltage. The aperture is designed to operate at K band frequencies (17.5 to 20.3 GHz), with a bandwidth of 2.8 GHz. We experimentally demonstrate imaging with a fabricated metasurface aperture using existing SAR modalities, showing image quality comparable to traditional antennas. The agility of this aperture allows it to operate in spotlight and stripmap SAR modes, as well as in a third modality inspired by computational imaging strategies. We describe its operation in detail, demonstrate high-quality imaging in both 2D and 3D, and examine various trade-offs governing the integration of dynamic metasurfaces in future SAR imaging platforms.

show abstract

“…To address this problem, we outline an alternative method based on the mode expansion of cylindrical waves propagating through the waveguide. This framework is particularly advantageous for modeling and designing planar structures [48,76]. We also demonstrate that the extracted polarizability of a metamaterial element depends on the geometry of the waveguide in which it is embedded.…”

Section: Introductionmentioning

confidence: 89%

“…Used as coatings, metasurfaces can control the absorbance and emissivity of a surface, and thus have relevance to thermophotovoltaics [34], detectors and sources [35][36][37][38][39][40][41]. Given the capabilities of metasurfaces to control waves, but without many of the limitations of volumetric metamaterials, metasurfaces have proven a good match for commercialization efforts, with many serious applications now being pursued, including satellite communications [42][43][44], radar [45], and microwave imaging [46][47][48].…”

Section: Introductionmentioning

confidence: 99%

“…The volume of the waveguide just beneath the element behaves as if filled with a material possessing effective constitutive parameters introduced by the presence of the metamaterial element [57]. In addition, the waveguide-fed metamaterial elements also leak energy out of the waveguide, such that the entire structure can act as an aperture antenna [48,58]. Indeed, metasurfaces can provide nearly total control over the wavefront in a manner similar to phased arrays [59] and other aperture antennas, but often with advantages not available in other formats [60][61][62][63][64].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Polarizability extraction of complementary metamaterial elements in waveguides for aperture modeling

et al. 2017

View full text Add to dashboard Cite

We consider the design and modeling of metasurfaces that couple energy from guided waves to propagating wavefronts. This is a first step towards a comprehensive, multiscale modeling platform for metasurface antennas-large arrays of metamaterial elements embedded in a waveguide structure that radiates intro free-space-in which the detailed electromagnetic responses of metamaterial elements are replaced by polarizable dipoles. We present two methods to extract the effective polarizability of a metamaterial element embedded in a one-or two-dimensional waveguide. The first method invokes surface equivalence principles, averaging over the effective surface currents and charges within an element to obtain the effective dipole moments; the second method is based on computing the coefficients of the scattered waves within the waveguide, from which the effective polarizability can be inferred. We demonstrate these methods on several variants of waveguidefed metasurface elements, finding excellent agreement between the two, as well as with analytical expressions derived for irises with simpler geometries. Extending the polarizability extraction technique to higher order multipoles, we confirm the validity of the dipole approximation for common metamaterial elements. With the effective polarizabilities of the metamaterial elements accurately determined, the radiated fields generated by a metasurface antenna (inside and outside the antenna) can be found self-consistently by including the interactions between polarizable dipoles. The dipole description provides an alternative language and computational framework for engineering metasurface antennas, holograms, lenses, beam-forming arrays, and other electrically large, waveguide-fed metasurface structures.

show abstract

Metamaterial microwave holographic imaging system

Cited by 154 publications

References 31 publications

Resolution of the Frequency Diverse Metamaterial Aperture Imager

Resolution of the Frequency Diverse Metamaterial Aperture Imager

Experimental Synthetic Aperture Radar With Dynamic Metasurfaces

Polarizability extraction of complementary metamaterial elements in waveguides for aperture modeling

Contact Info

Product

Resources

About