Wearable Slot Antenna at 2.45 GHz for Off-Body Radiation: Analysis of Efficiency,Frequency Shift, and Body Absorption

The interaction of body-worn antennas with the human body causes a significant decrease in antenna efficiency and a shift in resonant frequency. A resonant slot in a small conductive box placed on the body has been shown to reduce these effects. The specific absorption rate is less than internationa...

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Detalles Bibliográficos
Autores: Fernández Andrés, Marta, Espinosa, Hugo, Thiel, David, Arrinda Sanzberro, Amaia
Tipo de recurso: artículo
Fecha de publicación:2017
País:España
Institución:Universidad del País Vasco
Repositorio:Addi. Archivo Digital para la Docencia y la Investigación
OAI Identifier:oai:addi.ehu.eus:10810/68566
Acceso en línea:http://hdl.handle.net/10810/68566
Access Level:acceso abierto
Palabra clave:wearable antennas
power absorbed
antenna efficiency
resonant frequency shift
specific absorption rate
Descripción
Sumario:The interaction of body-worn antennas with the human body causes a significant decrease in antenna efficiency and a shift in resonant frequency. A resonant slot in a small conductive box placed on the body has been shown to reduce these effects. The specific absorption rate is less than international health standards for most wearable antennas due to small transmitter power.This paper reports the linear relationship between power absorbed by biological tissues at different locations on the body and radiation efficiency based on numerical modeling(r ¼ 0.99). While the 10 dB bandwidth of the antenna remained constant and equal to 12.5%,the maximum frequency shift occurred when the antenna was close to the elbow (6.61%) andon the thigh (5.86%). The smallest change was found on the torso (4.21%). Participants with body-mass index (BMI) between 17 and 29 kg/m 2 took part in experimental measurements,where the maximum frequency shift was 2.51%. Measurements showed better agreement with simulations on the upper arm. These experimental results demonstrate that the BMI for each individual had little effect on the performance of the antenna.