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Authors
Advisor(s)
Abstract(s)
Este projeto consiste no desenvolvimento de um Radar didático, um sistema funcional que permite a medição dos sinais em rádio frequência (RF) em diversos pontos ao longo das cadeias de transmissão e receção. Foram desenvolvidos dois protótipos com o hardware adaptado à técnica Stepped-Frequency Continuous Wave (SFCW) configurável para ajuste da potência de transmissão, ganho do recetor e tipo de mistura do Radar. Foi desenvolvido um protótipo inicial com uma potência de transmissão até 1 W (30 dBm), desenhado especificamente para a técnica SFCW, que integra apenas os blocos analógicos numa Placa de Circuito Impresso. Os protótipos são constituídos por componentes comercialmente disponíveis. O primeiro protótipo atingiu uma potência de transmissão máxima de 26 dBm, uma resolução em distância de 1 m e um alcance de 12 m. Durante o desenvolvimento, concluiu-se que uma potência de transmissão de 1 Watt requer um isolamento superior a 30 dB entre as duas antenas, o que não foi possível de alcançar, tendo reduzido significativamente a sensibilidade. A medição de um alvo estático e metálico foi alcançada em ambiente exterior às distâncias de 3, 6, 9 e 12 metros. O cancelamento da auto-interferência entre antenas foi estudado, concluindo que não é viável na implementação inicialmente proposta, tendo sido desenvolvido um segundo protótipo com uma revisão do método de cancelamento, assim como potência de transmissão máxima reduzida para 20 dBm. Com o segundo protótipo, foi demonstrado o cancelamento da auto-interferência em 18 dB à frequência de 1 GHz através do ajuste em amplitude e fase do sinal de cancelamento. Tanto o Radar desenvolvido inicialmente como a sua otimização, individualmente, contam com um baixo custo de desenvolvimento e construção, graças à utilização de componentes comerciais genéricos. Para a produção de 100 unidades, o custo dos componentes incluindo a PCB é inferior a 200€ por Radar.
This project consists in the development of a didactic Radar system, a functional system which allows for the analysis of the Radio-Frequency (RF) signals at different nodes of the transmitter and receiver. Two prototypes were developed with their hardware adapted to the Stepped-Frequency Continuous Wave (SFCW) technique, configurable for adjustment of transmission power, receiver gain and mixing type. An initial prototype was developed with a transmission power up to 1 W (30 dBm) specifically designed for the SFCW technique, and integrates only the analog segment in a Printed Circuit Board. The prototypes are built with commercially available components. The first prototype reached a maximum transmission power of 26 dBm, a measuring distance resolution of 1 m and a range of 12 m. During development, it was concluded that a transmission power of 1 Watt requires an isolation greater than 30 dB between the two antennas, which was not achieved, having significantly reduced the sensitivity. Measurement of a metallic static target was achieved in an outdoor environment at distances of 3, 6, 9 and 12 metres. The cancelling of antenna cross-talk was studied, concluding that the initially proposed implementation is not viable, leading to a second prototype being developed with a revised method for cancelling, as well as a reduced maximum transmission power to 20 dBm. With the second prototype, an antenna cross-talk cancelling of 18 dB was demonstrated through the adjustment of the cancelling signal’s amplitude and phase. Both the initially developed Radar and its optimisation have, individually, a low development and build cost, due to the use of commercially available generic omponents. For production of 100 units, the component cost including the PCB per Radar is lower than 200€..
This project consists in the development of a didactic Radar system, a functional system which allows for the analysis of the Radio-Frequency (RF) signals at different nodes of the transmitter and receiver. Two prototypes were developed with their hardware adapted to the Stepped-Frequency Continuous Wave (SFCW) technique, configurable for adjustment of transmission power, receiver gain and mixing type. An initial prototype was developed with a transmission power up to 1 W (30 dBm) specifically designed for the SFCW technique, and integrates only the analog segment in a Printed Circuit Board. The prototypes are built with commercially available components. The first prototype reached a maximum transmission power of 26 dBm, a measuring distance resolution of 1 m and a range of 12 m. During development, it was concluded that a transmission power of 1 Watt requires an isolation greater than 30 dB between the two antennas, which was not achieved, having significantly reduced the sensitivity. Measurement of a metallic static target was achieved in an outdoor environment at distances of 3, 6, 9 and 12 metres. The cancelling of antenna cross-talk was studied, concluding that the initially proposed implementation is not viable, leading to a second prototype being developed with a revised method for cancelling, as well as a reduced maximum transmission power to 20 dBm. With the second prototype, an antenna cross-talk cancelling of 18 dB was demonstrated through the adjustment of the cancelling signal’s amplitude and phase. Both the initially developed Radar and its optimisation have, individually, a low development and build cost, due to the use of commercially available generic omponents. For production of 100 units, the component cost including the PCB per Radar is lower than 200€..
Description
Trabalho final de Mestrado para obtenção do grau de Mestre em Engenharia Eletrónica e Telecomunicações
Keywords
SFCW, Radar didático Auto-interferência Phase-locked loop Homodino SFCW Didactic radar Cross-talk Phase-locked loop
Citation
Monteiro, Diogo Alexandre Farto - Radar didático de baixo custo baseado em SFCW para banda de UHF . Lisboa: Instituto Superior de Engenharia de Lisboa, 2023. Dissertação de Mestrado