Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spread-Spectrum Selective Camouflaging based on Time-Modulated
  Metasurface   This paper presents the concept of spread-spectrum selective camouflaging
based on time-modulated metasurface. The spectrum spreading is realized by
switching the metasurface between the reflective states of a PEC mirror and a
PMC mirror, using an array of microstrip patches connected to the ground via
diode switches, according to a periodic pseudo-random noise sequence. As the
spectrum spreading induces a drastic reduction of the power spectral density of
the signal, the level of the scattered wave falls below the noise floor of the
interrogating radar, and the object covered by the metasurface is hence
perfectly camouflaged to a foe radar. Moreover, the object can be detected by a
friend radar possessing the spread-spectrum demodulation key corresponding to
the metasurface modulation, and this detection is robust to interfering
signals. The proposed system is analyzed theoretically, and demonstrated by
both simulation and experimental results.

14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat