| Gastric cancer is one of the fatal chronic diseases with the widest impact and the largest number of people.Its early detection and treatment are the key to improving survival rate.Gastric slow wave detection is one of the effective methods for early detection of gastric cancer.The existing implantable gastric slow wave detection system adopts a method of data transmission percutaneously,one operation and one measurement,which is highly invasive and patients are prone to infection.Therefore,it is very important to study the implantable gastric slow wave detection system that can accurately detect the gastric slow wave and transmit the sensory data non-invasively and effectively to the outside of the body,and can safely operate for a long time.This paper first proposes a noninvasive two-channel data transmission implantable gastric slow wave detection(NI-DDT-IGSWD)system based on ultrasonic fiber grating(FBG)coupled array and radio frequency(RF)signal transmission technology.The formation mechanism of gastric slow wave is discussed in depth,and the model of gastric slow wave generation and propagation is given.The interaction process of ultrasonic wave and FBG and the transmitted light is analyzed,and the axial and radial coupling reflection spectrum of ultrasonic FBG is derived;the physical process of ultrasonic transcutaneous charging(UTET)is discussed,and the disc-type transducer is analyzed The sound field characteristics and distribution have laid a theoretical foundation for the optimized design of the NI-DDT-IGSWD system.A disc-type ultrasonic transducer model was established,and the influence of various parameters on energy transmission efficiency was analyzed.An optimization design method with PTE as the objective function is proposed,and the thickness and diameter of the transmitting and receiving transducers and the operating frequency are optimized respectively.The correctness of the method was verified by the finite element method simulation.Comparing the results of inductive coupling of 8 mm UTET module and the same size near field,the charging efficiency of the former with implant depth greater than 5 cm is about 5 times higher than that of the latter.The power management module for rectification,filtering and power protection is designed,and the influence of the power management module on the overall energy conversion efficiency is analyzed.According to the IEEE 802.15.6 protocol,the RF signal transmission channel is optimized,and the channel scheme at a rate of tens of kbps and power at the level of m W is given.The impact of transmission efficiency and distance on the data transmission performance is analyzed and discussed.Relationship curve between data transmission distance and packet loss rate.The influence of cyclic redundancy check codes on transmission stability is analyzed.A radio frequency data transmission channel experimental system based on CC1310 was established,and the best data packet length at 65 kbps was 131 bytes.The ultrasound FBG coupling channel model is established,and the difference between the single FBG diameter and axial coupling and the advantages of the axial coupling mode of ultrasound are analyzed and compared;the implant unit of the dual-channel gastric slow wave detection system is optimized,and the in vivo Integrated ultrasonic carrier signal transmission and energy receiving module,designed a single transducer to achieve ultrasonic charging and ultrasonic carrier signal transmission circuit timing;gives a wearable,ultrasonic FBG axial coupling array scheme. |
PDF Full Text Request