Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of transmission properties for waveguide bends by use of a
  circular photonic crystal   We study the transmission properties for the waveguide bends composed by a
circular photonic crystal. Two types (Y and U type) of the waveguide bends
utilizing the circular photonic crystal are studied. It has been shown,
compared with the conventional photonic crystal waveguide bends, transmission
properties for these bends can be significantly improved. Over a 6.4%
bandwidth, less than 1-dB loss/bend are observed. U bent waveguide, i.e.,
$180^o$ bend, can be easily realized with low loss using the circular photonic
crystal.

2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th