Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Adaptive antenna system by ESP32-PICO-D4 and its application to web
  radio system   Adaptive antenna technique has an important role in the IoT environment in
order to establish reliable and stable wireless communication in high
congestion situation. Even if knowing antenna characteristics in advance,
electromagnetic wave propagation in the non-line-of-sight environment is very
complex and unpredictable, therefore, the adjustment the antenna radiation for
the optimum signal reception is important for the better wireless link. This
article presents a simple but effective adaptive antenna system for Wi-Fi
utilizing the function of a highly integrated component, ESP32-PICO-D4. This
chip is a system-in-chip containing all components for Wi-Fi and Bluetooth
application except for antenna. Together with SP3T RF switch and dielectric
antennas and high-resolution audio DAC, completed web-radio system is made in
the size of 50 x 50 mm.

35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn