Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pencil-Beam Single-point-fed Dirac Leaky-Wave Antenna on a
  Transmission-Line Grid   Leaky-wave antennas (LWAs) are widely used as single-point-fed linear antenna
arrays. The extension of LWAs to 2D implies that they can be used as
single-point-fed 2D antenna arrays without requiring a complex feeding network.
However, generating a pencil beam from 2D LWAs is not straightforward and due
care has to be taken for the design of the LWA. On the other hand,
transmission-line (TL) grids have demonstrated interesting behaviors, such as
an effective negative refractive index and growing of evanescent waves. In this
paper, a singlepoint-fed TL-grid 2D Dirac leaky-wave antenna (DLWA) design is
proposed that generates a pencil beam at both broadside and slightly tilted
angles. The TL-grid unit cell is analytically treated in light of its
scattering and impedance matrices. The optimized TL-grid unit cell is shown to
exhibit a closed bandgap in the dispersion relation which is also linearly
varying with frequency (hence it is a DLWA). The proposed 2D DLWA design is
fabricated and the experimental results are presented.

24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess