Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Thin Electromagnetic Absorber for Wide Incidence Angles and Both
  Polarizations   In this paper a planar electromagnetic absorber is introduced whose
performance is maintained over a wide change of the incidence angle for both TE
and TM polarization. The absorber comprises an array of patches over a grounded
dielectric slab, with clear advantage in terms of manufacturability. It is
shown that a high value of the relative permittivity of the substrate is
essential for the operation of the absorber. The main contribution of the paper
is to demonstrate and practically use the presence of an additional resonance
of high-impedance surfaces when the plasma frequency of the wire medium
comprising metallic vias in the dielectric substrate is close to the original
resonance of the high-impedance surface. The presence of the vias between FSS
and the ground plane is discussed both for the case of a high-permittivity
absorber and for a low permittivity one. The radius of the vias influences the
oblique incidence TM absorption, and when properly designed, the insertion of
the vias result in bandwidth enlargement and higher absorption.

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The categories of this paper are: alg-geom
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th