Projeto de rede de antenas filamentares embarcada em um modelo real de aeronave radiocontrolada

Abstract

This work is based on the design of wire antenna arrays installed on a real model of unmanned aerial vehicle used in the SAE Brasil AeroDesign competition of 2014, built by Aeropampa aerodesign team of Universidade Federal do Pampa - UNIPAMPA. In this work, there is a secondary purpose, which is to seek to improve the performance of electromagnetic simulations through structural simplification, since the aircraft contained many details and it is over 36 times larger than the wavelength used (wingspan of the aircraft 1.868 𝑚 and wavelength of approximately 51.7 𝑚𝑚, operating frequency of 5.8 𝐺𝐻𝑧). Initially, it was necessary to generate the real model of the aircraft at mechanical simulation software SOLID WORKS, delivered by Aeropampa team. After this step, the positions were used in the antennas and the best electromagnetic simulation method offered by the software Ansys HFSS for complex structures presented by (LEMES, 2015). In this, the essence of the project was to work with an aircraft entirely composed of conductive material, where in aerodesign competitions, the chances of this actually occur are remote. However, this assumption is valid for other applications. In the present document, the aircraft model used consists of various materials, including: wood, polymer and metal. After the study of several monopole positions, the final location was chosen considering the best immunity of UAV (Unmanned Aerial Vehicle) structure and the least modification of the center of gravity. Thus, they settled two independent antennas arrays: one on each side of the fuselage and positioned at the junction between the wing and the fuselage. Thus, using a computer tool based on Particle Swarm Optimization (PSO) algorithm developed by (TOLFO, 2016), the studies of two feeding systems began, one for uniform distribution and another with beamforming. Both cases were evaluated in order to establish the communication link in the horizontal plane of the aircraft and the ground station, independent of the relative orientation between them. Thus, the uniform distribution prioritizes simplicity of the feeder system and the beam switching chooses to obtain higher gain. Finally, this document presents the feeder system design for uniform distribution, which was designed for operation band higher 200 𝑀𝐻𝑧, in order to provide some margin with respect to 105 𝑀𝐻𝑧 bandwidth regulated for the radiolocation service and amateur radio (5.725 𝐺𝐻𝑧 to 5.830 𝐺𝐻𝑧) by ANATEL (Agência Nacional de Telecomunicações) (TELECOMUNICAÇÕES, 2006). As a result, radiation pattern with a uniform distribution was obtained and was very close to the computational tool based on the PSO (both in simulation and in actual measurement). The gain was close to 2.5 𝑑𝐵𝑖 on the side of interest, input reection coe_cient was equal to -22.2 𝑑𝐵, bandwidth of approximately 750 𝑀𝐻𝑧 and added weight to the aircraft equal to 155.6 𝑔 (two antennas arrays, two transmission cables and a power divider).