Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Near-Field Angular Scan Enhancement of Antenna Arrays Using Metasurfaces   In this publication we continue our previous work on extending the angular
scan range of phased arrays using metasurfaces. We consider in detail scan
enhancement using a single metasurface lens in the near-field of a source and
provide analytical expressions for source excitation to obtain a desired beam.
We show that such a device suffers from the same directivity degradation as in
the case of far-field lens placement. Moreover, we discuss in detail that this
approach has limitations, and one cannot place the lens arbitrarily close to
the source array. We then propose a two-lens near-field scan enhancer which is
not subject to the same limitations, although still subject to the same
directivity degradation. Finally we propose a binary metasurface concept which
theoretically achieves desired scan enhancement without directivity
degradation. Some theoretical claims are then verified via full-field
simulations.

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The categories of this paper are: astro-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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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: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: math
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The categories of this paper are: supr-con
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The categories of this paper are: patt-sol