의료용 인체 삽입물을 위한 무선 저전력 송수신기에 관한 연구

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2016. 2. 남상욱.This thesis presents the wireless transceiver for medical implant application. The high propagation loss in human body which has high relative permittivity and conductive makes the implantable device be required for high sensitivity. Moreover, the device should have low power consumption to use for wireless implant medical application due to a restricted battery life. Also, this problem should be solved for on-body device considering integration with mobile device in the future. Simultaneously, the specific medical application such as epiretinal prosthesis, multi-channel electroencephalogram sensor demand high-data rate. Therefore, it is a main challenge that enhancing the devices power consumption and data-rate for implantable medical application. In order to enhance the performance of the device, several techniques are proposed in implantable human body transceivers. Firstly, the propagation loss in human-body is calculated for determine the frequency for medical implant application. The frequency bands allocated by FCC or MICS are too narrow and high lossy bands in human-body. For this reason, the optimum frequency for Implantable medical device is found by using Frisss formula and the link budget is calculated for capsule endoscopy system. The optimum frequency is verified through image recovery experiment in liquid human phantom and pig by using designed capsule endoscopy system. Secondly, the Super-Regenerative Receiver (SRR) with Digital Self-Quenching Loop (DSQL) is proposed for low power consumption. The proposed DSQL replaces the envelope detector used in a conventional SRR and minimizes power consumption by generating a self-quench signal digitally for a super-regenerative oscillator. The measurement results are given to show the performance of the proposed receiver. Thirdly, the RF Current Reused and Current Combining (CRCC) Power Amplifier (PA) is proposed for low power and high-speed transmitter. Normally, the PA having low output power has a feasibility issue that an optimum impedance of PA is too high to match with antenna impedance. For this reason, obtaining the maximum efficiency of PA is difficult for conventional structure. Moreover, conventional PAs output bandwidth is to be narrow due to high impedance transform ratio between PAs output and antennas input impedances. The CRCC structure solves this issue by decreasing the impedance transform ratio. The transmitter with CRCC PA is designed and verified through the measurement.Chapter 1. Introduction 1 1.1. WBAN (Wireless Body Area Network) 1 1.2. Challenges in Designing Transceiver for Medical Implant Application 7 Chapter 2. Propagation Loss in Human Body 10 2.1. Introduction 10 2.2. Far field approximation in human-body 13 2.3. Calculation of propagation loss in human-body 15 2.3.1. Frisss formula 15 2.3.2. Efficiency of transmitting antenna in human-body 17 2.4. Calculation of propagation loss in human-body and conclusion 19 Chapter 3. A Design of Transceiver for Capsule Endoscopy Application 21 3.1. Introduction 21 3.2. System Link Budget Calculation 24 3.3. Implementation 26 3.3.1. Transmitter with class B amplifier 26 3.3.2. Super-heterodyne receiver with AGC 28 3.3.3. Measurement results 30 3.4. Image recovery experiment 35 3.4.1. Integration of capsule endoscopy 35 3.4.2. Image recovery in the liquid human phantom 38 3.4.3. Image recovery in a pigs stomach and large intestine 40 3.5. Conclusion 41 Chapter 4. Super-Regenerative Receiver with Digitally Self-Quenching Loop 42 4.1. Introduction 42 4.1.1. Selection of receivers architecture for implantable medical device 44 4.1.2. Previous study of super-regenerative receiver 50 4.2. Main idea of proposed super-regenerative receiver 51 4.3. Description of proposed receiver 53 4.3.1. Digital self-quenching loop 55 4.3.2. Low noise amplifier and super-regenerative oscillator 57 4.3.3. Active RC filter for low power consumption 59 4.4. Experimental results 63 4.5. Summary and conclusion 69 Chapter 5. A Transmitter with Current-Reused and Current-Combining PA 71 5.1. Introduction 71 5.1.1. Previous study of OOK transmitter 72 5.2. Main idea of proposed transmitter 73 5.3. Description of proposed transmitter 79 5.3.1. Current-combining and current-reused PA 79 5.3.2. Ring oscillator with driving buffer 83 5.4. Experimental Results 85 5.5. Summary and conclusion 93 Chapter 6. Conclusion 95 Chapter 7. Appendix 97 7.1. Output spectrum of OOK signal 97 7.2. Theoretical BER of OOK comunication 99 Bibliography 101 초 록 109Docto

Design and Implementation of a Hybrid Wireless Power and Communication System for Medical Implants

Data collection and analysis from multiple implant nodes in humans can provide targeted medicine and treatment strategies that can prevent many chronic diseases. This data can be collected for a long time and processed using artificial intelligence (AI) techniques in a medical network for early detection and prevention of diseases. Additionally, machine learning (ML) algorithms can be applied for the analysis of big data for health monitoring of the population. Wireless powering, sensing, and communication are essential parts of future wireless implants that aim to achieve the aforementioned goals. In this paper, we present the technical development of a wireless implant that is powered by radio frequency (RF) at 401 MHz, with the sensor data being communicated to an on-body reader. The implant communication is based on two simultaneous wireless links: RF backscatter for implant-to-on-body communication and a galvanic link for intra-body implant-to-implant connectivity. It is demonstrated that RF powering, using the proposed compact antennas, can provide an efficient and integrable system for powering up to an 8 cm depth inside body tissues. Furthermore, the same antennas are utilized for backscatter and galvanic communication

A prototype design of wireless capsule endoscope.

by Chan Yawen.Thesis submitted in: September 12, 2005.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 57-64).Abstracts in English and Chinese.Acknowledgement --- p.iiAbstract --- p.iv摘要 --- p.viiTable of Contents --- p.ixList of Figures --- p.xiiList of Tables --- p.xivChapter Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Diseases of the Gastrointestinal (GI) Tract --- p.1Chapter 1.2 --- Wireless Capsule Endoscopy --- p.2Chapter 1.3 --- Goals of My Research Project --- p.9Chapter Part I - --- Experimental Study to Determine the Frequency of Wireless Transmission --- p.11Chapter Chapter 2 --- Background --- p.11Chapter 2.1 --- Analog and Digital Wireless Video Transmission --- p.11Chapter 2.2 --- "Industrial, Scientific and Medical (ISM) Bands" --- p.11Chapter 2.3 --- Adsorption of RP Energy by Biological Tissue --- p.13Chapter 2.4 --- Frequency used by Implanted/Ingested Devices --- p.13Chapter 2.5 --- Incentives of using Higher Frequencies --- p.14Chapter 2.6 --- Radiation Efficiency from an Implanted/Ingested Source --- p.15Chapter Chapter 3 --- Material and Method --- p.18Chapter 3.1 --- Human Body Trunk Experimental Model --- p.18Chapter 3.2 --- Radiating and Receiving Antennas --- p.19Chapter 3.3 --- Experimental Procedures --- p.21Chapter Chapter 4 --- Results and Discussions --- p.23Chapter Chapter 5 --- Conclusions --- p.30Chapter Part II - --- Prototype Design and Implementation --- p.31Chapter Chapter 6 --- Background --- p.31Chapter 6.1 --- Prototype Overview --- p.31Chapter 6.2 --- Digital and Analog Cameras --- p.32Chapter 6.3 --- Digital and Analog Transmitters --- p.34Chapter Chapter 7 --- Possible Solutions --- p.38Chapter 7.1 --- Analog Camera + Analog Video Transmission --- p.38Chapter 7.2 --- Digital Camera + Analog Video Transmission --- p.38Chapter 7.3 --- Digital Camera + Digital Video Transmission using WLAN Technology --- p.40Chapter 7.4 --- Digital Camera + Digital Video Transmission with Video Compression --- p.42Chapter Chapter 8 --- Implementation of the Analog Camera + Analog Transmission Solution --- p.44Chapter 8.1 --- Circuit Implementation --- p.44Chapter 8.2 --- System Verification --- p.49Chapter 8.3 --- Conclusions --- p.51Chapter Chapter 9 --- Conclusions and Future Work --- p.53Chapter 9.1 --- General Conclusions --- p.53Chapter 9.2 --- Future Work --- p.55List of Abbreviations --- p.6

Experimental Path Loss Models for In-Body Communications Within 2.36-2.5 GHz

"(c) 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works."Biomedical implantable sensors transmitting a variety of physiological signals have been proven very useful in the management of chronic diseases. Currently, the vast majority of these in-body wireless sensors communicate in frequencies below 1 GHz. Although the radio propagation losses through biological tissues may be lower in such frequencies, e.g., the medical implant communication services band of 402 to 405 MHz, the maximal channel bandwidths allowed therein constrain the implantable devices to low data rate transmissions. Novel and more sophisticated wireless in-body sensors and actuators may require higher data rate communication interfaces. Therefore, the radio spectrum above 1 GHz for the use of wearable medical sensing applications should be considered for in-body applications too. Wider channel bandwidths and smaller antenna sizes may be obtained in frequency bands above 1 GHz at the expense of larger propagation losses. Therefore, in this paper, we present a phantom-based radio propagation study for the frequency bands of 2360 to 2400 MHz, which has been set aside for wearable body area network nodes, and the industrial, scientific, medical band of 2400 to 2483.5 MHz. Three different channel scenarios were considered for the propagation measurements: in-body to in-body, in-body to on-body, and in-body to off-body.We provide for the first time path loss formulas for all these cases.Chavez-Santiago, R.; García Pardo, C.; Fornés Leal, A.; Vallés Lluch, A.; Vermeeren, G.; Joseph, W.; Balasingham, I.... (2015). Experimental Path Loss Models for In-Body Communications Within 2.36-2.5 GHz. IEEE Journal of Biomedical and Health Informatics. 19(3):930-937. doi:10.1109/JBHI.2015.2418757S93093719

Nano-Communication for Biomedical Applications: A Review on the State-of-the-Art From Physical Layers to Novel Networking Concepts

We review EM modeling of the human body, which is essential for in vivo wireless communication channel characterization; discuss EM wave propagation through human tissues; present the choice of operational frequencies based on current standards and examine their effects on communication system performance; discuss the challenges of in vivo antenna design, as the antenna is generally considered to be an integral part of the in vivo channel; review the propagation models for the in vivo wireless communication channel and discuss the main differences relative to the ex vivo channel; and address several open research problems and future research directions