应用于移动医疗的三频段植入式天线研究

发布时间：2018-06-13 03:46

本文选题：植入式天线 + 小型化　；参考：《西南交通大学》2017年硕士论文

【摘要】：随着人口老龄化问题的不断加剧和亚健康人群的不断增加,移动医疗技术因其在个人医疗保健中的重要应用逐渐受到人们的关注,并成为未来生物医学的发展趋势。植入式医疗设备工作在人体内,对病人的生理参数进行实时监测,为疾病预防、诊断及治疗提供信息。同时,它能为患者提供更舒适的治疗环境和服务。植入式医疗设备与外部设备的数据传输是通过天线完成的。小的天线尺寸不仅能提高患者的舒适度,还能增加对人体位置的敏感度,提高通信质量,而优良的天线性能也是植入式医疗设备进行精确数据遥测的重要前提。体内外的无线能量传输能延长植入式医疗设备的工作寿命,这对于植入式医疗设备长期、稳定的工作至关重要。因此,在人们生活水平和个人健康意识不断提高的今天,对移动医疗中植入式天线与无线能量传输的研究具有非常重要的价值和意义,但是复杂的人体环境给植入式天线的设计带来了新的要求与挑战。本文对应用于无线医疗设备中的植入式天线以及无线能量传输技术进行了研究,主要工作包括:首先,采用高介电常数介质板和蜿蜒结构平面倒F天线减小天线尺寸,设计了一款紧凑的三频段医疗植入式天线,天线尺寸为20mm × 15mm × 0.5mm,工作频率为MICS频段(404MHz),WMTS频段(1.43GHz)和ISM频段(2.45GHz)。对天线参数进行优化后,天线在三个频点处的阻抗带宽分别为382-416MHz(8.4%),1.41-1.48GHz(4.9%)和 2.28-2.6GHz(13.1%),同时保持了-37.3,-25.7 和-19.1dB 的远场增益。对设计的植入式天线,分析了不同植入情况下天线辐射性能的改变。为了进一步减小天线尺寸,采用高介电常数介质板与多层平面倒F天线相结合,设计了一款三频段植入式天线,天线同样覆盖了 MICS频段和WMTS频段,还覆盖了 ISM频段(918MHz),天线结构紧凑,尺寸仅10mm× 10mm × 1.5mm。对天线性能影响较大的参数进行了优化,最终,天线在各频点处回波损耗小于-15dB,增益分别为-39,-33,-26dB,保证了天线工作的可靠性。同时,考虑到天线辐射带来的人体安全问题,对天线各频段的SAR(比吸收率)值进行了预估。最后,基于仿真模型制作了天线实物,用猪肉模拟人体组织进行了实测,实测数据与仿真结果吻合良好。为了解决医疗植入式设备中的供电问题,系统地研究了植入式系统中的无线能量传输技术。远场无线能量传输必须考虑人体安全,首先基于所设计的植入式天线,在满足各项安全规定的情况下,计算了 918MHz处植入式天线能接受到的功率,以此确定整流电路的输入功率范围,对整流电路的转换效率进行优化。然后,以提高转换效率为目标,对整流电路中负载、电容和电感等进行了优化。最终,在输入功率为5dBm时获得了 69.4%的转换效率,负载上直流电压达到3.5V,足够提供植入式医疗设备所需的能量,使植入式医疗设备长时间、稳定地工作。
[Abstract]:With the aggravation of population aging and the increasing of sub-health population, mobile medical technology has been paid more and more attention because of its important application in personal medical care, and has become the development trend of biomedicine in the future. Implantable medical devices work in the human body and monitor the physiological parameters of patients in real time to provide information for disease prevention, diagnosis and treatment. At the same time, it can provide patients with a more comfortable treatment environment and services. Data transmission between implantable medical devices and external devices is accomplished by antenna. Small antenna size can not only improve the comfort of patients, but also increase the sensitivity of human body position, improve the quality of communication, and excellent antenna performance is also an important prerequisite for accurate telemetry of implantable medical equipment. Wireless energy transmission in vivo and in vitro can prolong the working life of implanted medical devices, which is very important for the long-term and stable operation of implanted medical devices. Therefore, with the improvement of people's living standard and personal health awareness, the research on implanted antennas and wireless energy transmission in mobile medicine is of great value and significance. However, the complex human environment brings new requirements and challenges to the design of implanted antennas. In this paper, the implanted antenna and wireless energy transmission technology used in wireless medical equipment are studied. The main work includes: firstly, using high dielectric constant dielectric plate and meandering planar inverted F antenna to reduce the antenna size. A compact three-band medical implantable antenna is designed. The antenna size is 20mm 脳 15mm 脳 0.5mm, and the operating frequency is 404MHz (1.43GHz) and 2.45GHz. After the antenna parameters are optimized, the impedance bandwidth of the antenna at the three frequency points is 382-416MHz / 8.4mm and 1.41-1.48GHz / 4.9b) and 2.28-2.6GHz / 13.1dB respectively, while maintaining the far-field gains of -37.37-25.7 and -19.1dB respectively. The radiation performance of the implanted antenna under different implanted conditions is analyzed. In order to further reduce the antenna size, a three-band implanted antenna is designed by combining the high dielectric constant dielectric plate with the multi-layer plane inverted F antenna. The antenna also covers the mics band and the WMTS band. The structure of the antenna is compact and the size is only 10mm 脳 10mm 脳 1.5mm. Finally, the antenna echo loss is less than -15dB at each frequency point, and the gain is -39ng-33ng-26dB, which ensures the reliability of antenna operation. At the same time, considering the human safety problem caused by antenna radiation, the SAR (specific absorptivity) value of the antenna is estimated. Finally, the antenna object is made based on the simulation model, and the actual measurement is carried out by simulating human tissues with pork. The measured data agree well with the simulation results. In order to solve the problem of power supply in medical implantable devices, wireless energy transmission technology in implantable systems is studied systematically. The safety of human body must be considered in far-field wireless energy transmission. Firstly, based on the designed implanted antenna, the power of the implanted antenna at 918MHz is calculated under the condition of satisfying the security regulations. The input power range of rectifier circuit is determined and the conversion efficiency of rectifier circuit is optimized. Then, the load, capacitance and inductance of rectifier circuit are optimized to improve the conversion efficiency. Finally, when the input power is 5 dBm, the conversion efficiency is 69.4%, and the DC voltage on the load reaches 3.5 V, which is enough to provide the energy needed for the implantable medical equipment and make the implanted medical equipment work stably for a long time.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN820

【参考文献】