Research On Implantable Antenna For Wireless Biomedical Telemetry

With the continuous development of social economy,health issues are attracting more and more people’s attention.Wireless biomedical telemetry technology collects patients’ physiological indicators in real time through wireless implantable devices inside patients’ bodies and sends them to medical terminals to ensure patients’ life safety.As an important part of the wireless implantable device,the implantable antenna is responsible for real-time communication and data transmission with the external device.Therefore,a well-designed implantable antenna is essential for the stable operation of wireless implantable devices.Considering the special working environment of implantable antennas,the miniaturization,gain,specific absorption rate and energy consumption of antennas should be considered in the design.In this thesis,several implantable antennas with different functions are studied,and the main work includes:(1)Broadband circular polarization implantable antenna: a broadband circularly polarized implantable antenna is proposed.The dimensions of the antenna are 9.8mm×9.8 mm×0.889 mm,after simulation,the impedance bandwidth and the axial ratio bandwidth of the antenna are 2.09-2.62 GHz(21.6 %)and 2.21-2.97 GHz(31 %),respectively.This thesis analyses the operating principles of antenna and discusses the impact of antenna-related parameters on performance.A flat-type implantable device is also presented to verify the effect of integration on antenna performance.Based on the verification of the antenna performance in a high-precision human body model,the antenna was processed and tested on a sample.Finally,the link margin between the antenna and the in vitro receiving antenna was analyzed and the wireless communication performance of the antenna was evaluated.(2)Dual-band implantable antenna: Aiming at miniaturization and dual-band of the implantable antenna,a dual-band implantable antenna that can cover 0.9 GHz ISM band and 2.4 GHz ISM band is designed.The impedance bandwidth of the antenna is 0.87-0.96 GHz(9.9 %)and 2.19-2.86 GHz(27.3 %)for the two operating bands,and the peak gain is-23.8 dBi and-19 dBi in the two operating bands,respectively.this thesis analyses the principles of miniaturization and dual-banding of antenna,discusses and analyses the SAR value of antennas,the effect of antenna-related parameters on performance and the communication link budget.(3)MIMO implantable antenna: A MIMO implantable antenna operating in the 0.9GHz ISM band is designed,which has two structurally symmetrical radiating units.The operating band of the antenna is 0.86-0.94 GHz(8.8 %),and the isolation in the full band is not less than 23 dB.In this thesis,the miniaturization principle of the antenna and the decoupling principle are analyzed,and the MIMO channel parameters of the antenna and the relevant key parameters affecting the antenna performance are discussed.