Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultra-wideband Reflection-type Metasurface for Generating Integer and
  Fractional Orbital Angular Momentum   Vortex beams carrying orbital angular momentum are extensively studied owing
to its potential to expand channel capacity of microwave and optical
communication. By utilizing the Pancharatnam-Berry phase concept, an
ultra-wideband single layer metasurface is proposed to realize the conversion
from incident plane waves to reflected vortex beams covering a considerable
bandwidth from 6.75 to 21.85 GHz . An equivalent circuit model combined with
broadband phase shift network is developed to effectively design the meta-atoms
in metasurface. It is the first time to design wideband metasurfaces with the
phase-based characteristics. To verify the proposed model, some deformed square
loop meta-atoms are proposed to construct the metasurfaces with broadband OAM
characteristic. Moreover, the vortex beams with the integer (l = -3),
fractional (l = -1.5), and high-order (l = -10) OAM mode are generated
respectively. Based on an OAM spectral analysis, the mode purity of the
generated vortex waves is discussed in detail. The experimental results achieve
a good agreement with those obtained from the simulation, thus proving the
effectiveness and practicability of the proposed method.

19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph