植入式医疗器械中的差分分形天线研究

发布时间：2018-08-28 10:04

【摘要】：植入式医疗器械相对体外设备而言能够更加精确且方便地获得人体生理参数的相关数据,因此,植入式医疗器械在医疗诊断、监测和治疗领域中的应用受到了越来越多的关注。植入式天线是植入式医疗器械进行无线通信的关键器件,用以实现将医疗传感器采集到的生理医学数据用无线方式传输到体外接收设备。由于植入式天线的特殊工作环境,对天线尺寸的缩小、抗干扰能力的提高、使用寿命的延长等提出了新的挑战。本论文是由国家自然科学基金(61372008)、广东省科技计划项目(2014A010103014,2015B010101006)等项目资助,主要研究应用于植入式医疗器械中的差分分形天线。本研究课题主要工作内容有:植入式天线的特殊工作环境要求我们在一开始设计天线时就应当将人体的影响考虑在内,为此本研究分别建立了结构较简单的人体模型和高精度的人体模型。(1)工作在MICS频段的差分分形植入式天线:差分馈电技术的采用使得天线能够直接的与植入式医疗器械中差分电路链接,提高了共模噪声的抑制能力。通过采用分形曲线、高介电常数基板等方式实现天线的小型化,尺寸为9.3×9.3×0.635 mm3。天线覆盖医疗与植入式通信服务(MICS)频段,带宽为67 MHz(374 441 MHz)。文中介绍了高精度人体建模过程并分析了天线远场增益和与人体安全相关的比吸收率(SAR)值。为了进一步降低植入式设备的功耗,延长其使用周期,本文在单频天线的基础上,通过改进与优化研究设计了一款植入式双频天线。(2)应用于植入式医疗器械中的差分分形双频天线:天线覆盖MICS频段和2.44GHz工业、科学和医疗(ISM)频段。天线的双频特性允许植入式设备进入睡眠模式以降低功耗,需要通信时可通过ISM频段发送唤醒信号使其进入工作模式。文中分析了天线工作原理,给出了定量研究天线噪声抑制能力的参数并分析了天线获得高噪声抑制能力的原理。研究了关键参数对天线性能的影响,分析了天线的辐射性能、SAR以及评估天线通信性能的链路预算等。对天线实物进行了制备,测量与仿真结果基本吻合,验证了理论设计的准确性。(3)差分植入式双频宽带分形天线:由于天线植入到不同电特性组织中时会产生频率偏移,为了提高植入式天线的鲁棒性,降低频偏对其性能的影响,本文通过实现临近双谐振频点来扩展天线的带宽。天线在MICS和ISM频段带宽分别为22.1%和41%。文中分析了天线的演化过程和天线的相关尺寸,增益,SAR等参数,并研究了天线的输入功率与最大通信速率的关系,给出了天线以所需通信速率工作时人体的温度分布。本研究表明,差分结构天线对提高系统集成度、抑制共模噪声以及降低功耗等方面有重要作用,分形结构在天线的小型化方面有明显的优势。差分分形天线的研究能够进一步的提高系统的集成度和噪声抑制能力,降低系统功耗,缩小天线的体积。
[Abstract]:Implantable medical devices can obtain the relevant data of human physiological parameters more accurately and conveniently than external devices. Therefore, the application of implantable medical devices in the field of medical diagnosis, monitoring and treatment has attracted more and more attention. Implantable antenna is the key device for wireless communication of implantable medical devices to realize wireless transmission of physiological and medical data collected by medical sensors to the receiving equipment in vitro. Due to the special working environment of the implanted antenna, it presents new challenges to the reduction of antenna size, the improvement of anti-jamming ability and the prolongation of service life. This paper is supported by the National Natural Science Foundation of China (61372008) and the Guangdong Science and Technology Project (2014A010103014A2015B010101006). The main work of this research is as follows: the special working environment of the implanted antenna requires us to take the human body's influence into account when we design the antenna at the beginning. In this study, the simple human body model and the high precision human body model were established respectively. (1) the differential fractal implanted antenna working in the MICS band: the differential feed technology enables the antenna to be directly and directly implanted with the implanted medicine. (1) the differential Fractal Implant Antenna working in the MICS band. A differential circuit link in a therapeutic device, The suppression ability of common-mode noise is improved. The antenna is miniaturized by means of fractal curve and high dielectric constant substrate. The size of antenna is 9.3 脳 9.3 脳 0.635 mm3.. The antenna covers the (MICS) band of medical and implantable communications services with a bandwidth of 67 MHz (374,441 MHz).) In this paper, the process of high precision modeling of human body is introduced, and the far-field gain of antenna and the specific absorptivity (SAR) value related to human safety are analyzed. In order to further reduce the power consumption of the implanted device and prolong its life cycle, this paper based on the single frequency antenna, An implantable dual-frequency antenna is designed through improved and optimized research. (2) the differential fractal dual-frequency antenna used in implantable medical devices: the antenna covers the MICS band and the 2.44GHz industrial, scientific and medical (ISM) band. The dual-frequency characteristic of the antenna allows the implanted device to enter sleep mode to reduce power consumption. When communication is needed, a wake-up signal can be sent through the ISM band to enable the device to enter working mode. In this paper, the working principle of antenna is analyzed, the parameters of quantitatively studying antenna noise suppression ability are given, and the principle of antenna obtaining high noise suppression ability is analyzed. The influence of key parameters on antenna performance is studied. The radiation performance of antenna and the link budget to evaluate antenna communication performance are analyzed. The antenna is fabricated, and the measurement results are in good agreement with the simulation results, which verify the accuracy of the theoretical design. (3) differential implanted dual-band wideband fractal antenna: because of the antenna implanted into different electrical characteristics of the tissue will produce frequency offset, In order to improve the robustness of the implanted antenna and reduce the influence of frequency offset on its performance, this paper extends the bandwidth of the antenna by realizing near the double resonant frequency point. The bandwidth of the antenna in the MICS and ISM bands is 22. 1% and 41. 1%, respectively. In this paper, the evolution process of the antenna, the relative size of the antenna, the gain SAR and other parameters are analyzed. The relationship between the input power of the antenna and the maximum communication rate is studied, and the temperature distribution of the human body when the antenna works at the desired communication rate is given. The results show that differential antenna plays an important role in improving system integration, suppressing common-mode noise and reducing power consumption. Fractal structure has obvious advantages in antenna miniaturization. The research of differential fractal antenna can further improve the integration and noise suppression ability of the system, reduce the power consumption of the system, and reduce the size of the antenna.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN822;TH789

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