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Authors
Advisor(s)
Abstract(s)
À semelhança de muitas outras áreas, o campo da medicina tem experimentado novas descobertas e aplicações extraordinárias que fazem com que existam alternativas cada vez mais inovadoras, de modo a melhorar a nossa qualidade de vida. As técnicas de aplicabilidade dos dispositivos médicos implantáveis são um exemplo de como o avanço da tecnologia veio facilitar algumas intervenções cirúrgicas, tornando-as também mais confortáveis para o paciente. No entanto, estes possuem também algumas desvantagens, sendo umas delas a necessidade de usar baterias como fonte de alimentação do dispositivo. Como consequência, estes implantes apresentam um tempo de vida limitado que é geralmente ditado pelo tamanho e capacidade das baterias, e que implica a sua troca com alguma periocidade, trazendo complicações para o paciente.
De modo a solucionar este problema, nos últimos anos têm surgido diversos estudos de sistemas que usam antenas para transferir potência para o interior do organismo. No entanto, um dos problemas desta solução é o valor elevado de potência que é refletida quando a antena é colocada em contacto com o corpo humano, causando a desadaptação da mesma. Neste âmbito, e com o objetivo de resolver os problemas descritos, pretendeu-se com esta dissertação apresentar uma antena de dimensões reduzidas, passível de ser utilizada na transferência de potência sem fios, de forma a alimentar um possível dispositivo médico implantável. Para isso, desenhou-se, simulou-se e otimizou-se uma antena para uma banda ISM (902-928 MHz), de modo a estar em contacto com o corpo tendo em conta as propriedades dielétricas e respetivas espessuras das várias camadas do tecido humano. Foram ainda explorados e comparados dois substratos diferentes, nomeadamente o DuPont 951 LTCC (low-temperature cofired ceramics), muito utilizado neste tipo de aplicações e o Rogers RO4360G2, como um material facilmente disponível.
Depois de construída o desempenho da antena foi testado numa pessoa e os resultados obtidos foram bastante promissores, permitindo desta forma apresentar uma solução que pode ser interessante num futuro próximo.
Like many other areas, the field of medicine has been experiencing new discoveries and extraordinary applications that make alternatives increasingly more innovative, in order to improve our quality of life. The techniques that use mplantable medical devices are an example of how the technology innovation has facilitated some surgical interventions, also making them more comfortable for the patient. However, they also have some disadvantages, one of which is the need to use batteries as power source. Hence, these implants have a limited lifetime that is usually dictated by the size and capacity of the batteries, and that implies their replacement with some periodicity, causing complications for the patient. In order to solve this problem, in recent years, there were several studies of systems that use antennas to transfer power into the body. However, one of the problems with this solution is the high power reflection when the antenna is located in contact with the human body, as it might affect its resonance. In this context and in order to solve the problems described, this dissertation intends to present an antenna with reduced dimensions, which can be used in wireless power transfer, in order to supply a possible implantable medical device. For this purpose, an antenna for the ISM band (902-928 MHz) was designed, simulated and optimized, in order to be in contact with the body, taking into account the dielectric properties and respective thicknesses of the various human tissue layers. Two different substrates were also explored and compared, namely the DuPont 951 LTCC (low-temperature cofired ceramics), widely used in this type of applications and the Rogers RO4360G2, as an easily available material. After the antenna was built, it was tested on a person and the results obtained were very promising, thus allowing to present a solution that may be interesting in the near future.
Like many other areas, the field of medicine has been experiencing new discoveries and extraordinary applications that make alternatives increasingly more innovative, in order to improve our quality of life. The techniques that use mplantable medical devices are an example of how the technology innovation has facilitated some surgical interventions, also making them more comfortable for the patient. However, they also have some disadvantages, one of which is the need to use batteries as power source. Hence, these implants have a limited lifetime that is usually dictated by the size and capacity of the batteries, and that implies their replacement with some periodicity, causing complications for the patient. In order to solve this problem, in recent years, there were several studies of systems that use antennas to transfer power into the body. However, one of the problems with this solution is the high power reflection when the antenna is located in contact with the human body, as it might affect its resonance. In this context and in order to solve the problems described, this dissertation intends to present an antenna with reduced dimensions, which can be used in wireless power transfer, in order to supply a possible implantable medical device. For this purpose, an antenna for the ISM band (902-928 MHz) was designed, simulated and optimized, in order to be in contact with the body, taking into account the dielectric properties and respective thicknesses of the various human tissue layers. Two different substrates were also explored and compared, namely the DuPont 951 LTCC (low-temperature cofired ceramics), widely used in this type of applications and the Rogers RO4360G2, as an easily available material. After the antenna was built, it was tested on a person and the results obtained were very promising, thus allowing to present a solution that may be interesting in the near future.
Description
Trabalho Final de Mestrado para Obtenção do Grau de Mestre em Engenharia Biomédica
Keywords
Antenas Dispositivos biomédicos
Citation
FERREIRA, Luís Henrique Ribeiro – Antena para transferência de potência sem fios para alimentação de dispositivos biomédicos. Lisboa: Instituto Superior de Engenharia de Lisboa, 2021. Dissertação de Mestrado
Publisher
Instituto Superior de Engenharia de Lisboa