Resumo:
The handheld devices for the fifth-generation (5G) of mobile communications will support
diverse services using different frequency bands, including the Second Frequency Range
(FR2), from 24.25 GHz to 52.60 GHz. This millimeter-wave (mm-waves) bandwidth provides
high data rates, i.e. ≈2.15 Gbit/s for downlink and ≈2.37 Mbit/s up-link, however,
the characteristics of the channels, devices manufacturing, and the high free space losses
are some of the limiting factors of this frequency range. The network effectiveness will
then depend directly on the use of high-performance antennas, reconfigurable devices,
reduced costs, among other aspects. Taking advantage of the needs of 5G systems, this
thesis presents a low-cost (initial prototype worth ≈250 reais), lightweight antenna array
with reconfigurable two-dimensional beam steering (azimuth and elevation) to operate in
millimeter waves. The main innovation is the antenna feed network based on metamaterials
with low insertion loss, linearity operation, and reduced stage number. This network
performs the beam steering through phase reconfiguration without interfering with the
antenna array performance. Additionally, a parasitic patches technique was applied in
order to improve gain and bandwidth. The project methodology is based on analytical
calculations and numerical simulations were carried out using the software Ansys HFSS.
The array performance has been analyzed in terms of the mutual coupling to evaluate its
possible application in a multi-antennas system. The approach has a total size of 6×6 cm,
compact enough to operate inside a mobile phone. All pre-set design requirements were
achieved, resulting in an antenna array gain of 12.5 dBi, 2.8 GHz bandwidth, reconfigurability
of 20∘, sidelobe level below 10 dB and mutual coupling lower than -50 dB.
