ALBUQUERQUE, T. C.; http://lattes.cnpq.br/3548518251493336; ALBUQUERQUE, Túlio Chaves de.
Resumo:
The objective of this internship was the study, the simulation and the realization of
microwave circuits for beam-steering systems applications at 5.8 GHz. More specifically, this
work involved Power Dividers, Reflexion Type Phase Shifters and microstrip antennas. For
the divider, a topology in the state-of-the-art was used. It is an adaptation of the classic
Wilkinson’s power divider. In the presented topology, two supplementary transmission lines
are used between the output ports and the resistance, in addition of a stub that is placed in the
input port’s junction. The phase shifter used in this work is also in the state-of-the-art and is
composed of a codirective hybrid coupler with reflective networks in two of its four terminals.
These reflective networks are composed of a transmission line and three varactors. By varying
the varactors’ capacitance, the output signal has its phase changed while its amplitude stays
the same as the input signal. Dipole antennas were used due to their radiation pattern.
Simulations were made with CST Microwave Studio and ADS. After fabrication, the devices
were tested with vector network analyzer and anechoic chamber. Some parameters verified
were insertion and return losses as well as radiation pattern. Since these are the first results,
they are very promising and they pave the way for research and optimization of devices and
the whole system.
