ABSTRACT

Wireless biotelemetry enables the formation of communication link from living body to an external monitoring device. Isolation of near field electromagnetic (EM) waves from body tissue, and wide bandwidth to avoid frequency detuning in different biological environments are the important parameters of on-body antennas. In this paper, a conformal defected ground patch antenna with artificial magnetic conductor (AMC) is introduced for on-body communication. Initially, a quarter wave wide band antenna with a shorting pin is designed to operate at 2.45 GHz. It resonates effectively on body tissue but most of the near field EM radiations are absorbed by tissue. Poor radiation efficiency of 10% and high specific absorption rate (SAR) value of 7.73 W/Kg were obtained. Thus, to reduce the effect of tissue loading on antenna performance an AMC-based structure is added. Better impedance matching, high efficiency (65%) and directivity (7.3 dBi) is achieved with AMC structure. Furthermore, unidirectional radiation pattern with SAR value of 1.43W/Kg is attained. Wide bandwidth of 600 MHz on phantom enables the antenna to withstand frequency detuning effect due to body postures and movements. Antenna robustness is analysed by bending the structure at different radii along X-axis and Y-axis.

摘要

无线生物遥测技术能够形成从活体到外部监测设备的通信链路。将近场电磁 (EM) 波与身体组织隔离，以及避免不同生物环境中的频率失谐的宽带宽是体载天线的重要参数。在本文中，介绍了一种带有人工磁导体 (AMC) 的共形缺陷接地贴片天线，用于人体通信。最初，带有短路针的四分之一波宽带天线设计为在 2.45 GHz 下运行。它在身体组织上有效共振，但大部分近场 EM 辐射被组织吸收。获得了 10% 的低辐射效率和 7.73 W/Kg 的高比吸收率 (SAR) 值。因此，为了减少组织负载对天线性能的影响，添加了基于 AMC 的结构。AMC 结构实现了更好的阻抗匹配、高效率 (65%) 和方向性 (7.3 dBi)。此外，获得了 SAR 值为 1.43W/Kg 的单向辐射图。幻像上 600 MHz 的宽带宽使天线能够承受由于身体姿势和运动引起的频率失谐效应。通过沿 X 轴和 Y 轴以不同半径弯曲结构来分析天线的鲁棒性。