Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Design of Passive and Lossless Single Layer Metasurfaces for Far Field
  Beamforming   A general synthesis technique for beamforming metasurfaces is presented which
utilizes accurate modeling techniques and rapid optimization methods. The
metasurfaces considered consist of patterned metallic claddings supported by
finite grounded dielectric substrates. The metasurfaces are modeled using
integral equations which accurately account for all mutual coupling and finite
dimensions. A beamforming metasurface is designed in three phases: an initial
Direct Solve phase involving the solution of the integral equation via the
method of moments to obtain a complex-valued initial design satisfying the
desired far-field beam specifications, a subsequent Optimization phase to
convert the complex-valued metasurface into a purely reactive metasurface, and
a final Patterning phase to realize the metasurface as a patterned metallic
cladding. The metasurface is optimized using gradient descent with a
semi-analytic gradient obtained from the Adjoint field method. The optimization
phase introduces surface waves which facilitate passivity. A novel surface
impedance extraction approach for aperiodic unit cell environments is used to
pattern the metallic cladding of the metasurfaces. Several examples are
presented, including a scanned beam reflectarray design with low sidelobes, a
low-profile directly-fed meta-antenna with 100% aperture efficiency, and a
conformal metasurface reflectarray.

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The categories of this paper are: atom-ph
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The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: cs
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg