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Xia F, Li H, Li Y, Liu X, Xu Y, Fang C, Hou Q, Lin S, Zhang Z, Yang J, Sawan M. Minimally Invasive Hypoglossal Nerve Stimulator Enabled by ECG Sensor and WPT to Manage Obstructive Sleep Apnea. SENSORS (BASEL, SWITZERLAND) 2023; 23:8882. [PMID: 37960581 PMCID: PMC10648123 DOI: 10.3390/s23218882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 10/27/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023]
Abstract
A hypoglossal nerve stimulator (HGNS) is an invasive device that is used to treat obstructive sleep apnea (OSA) through electrical stimulation. The conventional implantable HGNS device consists of a stimuli generator, a breathing sensor, and electrodes connected to the hypoglossal nerve via leads. However, this implant is bulky and causes significant trauma. In this paper, we propose a minimally invasive HGNS based on an electrocardiogram (ECG) sensor and wireless power transfer (WPT), consisting of a wearable breathing monitor and an implantable stimulator. The breathing external monitor utilizes an ECG sensor to identify abnormal breathing patterns associated with OSA with 88.68% accuracy, achieved through the utilization of a convolutional neural network (CNN) algorithm. With a skin thickness of 5 mm and a receiving coil diameter of 9 mm, the power conversion efficiency was measured as 31.8%. The implantable device, on the other hand, is composed of a front-end CMOS power management module (PMM), a binary-phase-shift-keying (BPSK)-based data demodulator, and a bipolar biphasic current stimuli generator. The PMM, with a silicon area of 0.06 mm2 (excluding PADs), demonstrated a power conversion efficiency of 77.5% when operating at a receiving frequency of 2 MHz. Furthermore, it offers three-voltage options (1.2 V, 1.8 V, and 3.1 V). Within the data receiver component, a low-power BPSK demodulator was ingeniously incorporated, consuming only 42 μW when supplied with a voltage of 0.7 V. The performance was achieved through the implementation of the self-biased phase-locked-loop (PLL) technique. The stimuli generator delivers biphasic constant currents, providing a 5 bit programmable range spanning from 0 to 2.4 mA. The functionality of the proposed ECG- and WPT-based HGNS was validated, representing a highly promising solution for the effective management of OSA, all while minimizing the trauma and space requirements.
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Affiliation(s)
- Fen Xia
- Zhejiang University, Hangzhou 310024, China;
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
| | - Hanrui Li
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
- SAMA Labs, Computer, Electrical and Mathematical Science and Engineering (CEMSE) Division, Department of Electrical and Computer Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Yixi Li
- State Key Laboratory of Superlattices, Microstructures Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100045, China;
| | - Xing Liu
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
| | - Yankun Xu
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
| | - Chaoming Fang
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
| | - Qiming Hou
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
| | - Siyu Lin
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
| | - Zhao Zhang
- SAMA Labs, Computer, Electrical and Mathematical Science and Engineering (CEMSE) Division, Department of Electrical and Computer Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Jie Yang
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
| | - Mohamad Sawan
- CenBRAIN Laboratory, School of Engineering, Westlake University, Hangzhou 310024, China; (H.L.)
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Kouhalvandi L, Ozoguz S, Koohestani M. A Literature Survey with the Focus on Magnetically Coupled Wireless Power Transfer Systems Developed for Engineering and Biomedical Applications. MICROMACHINES 2023; 14:786. [PMID: 37421019 DOI: 10.3390/mi14040786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/26/2023] [Accepted: 03/29/2023] [Indexed: 07/09/2023]
Abstract
Wireless power transfer (WPT) is the transmission of electrical energy to other external/internal devices without the need for wire connection. Such a system is useful to power electrical devices as a promising technology for various emerging applications. The implementation of devices integrated with WPT alters the existing technologies and enhance the theoretical concept for future works. Over the last decade, various studies have been conducted on the applications of magnetically coupled WPT systems, where a general overview over such devices would be beneficial. Hence, this paper presents a comprehensive review over various WPT systems developed for commercially existing applications. The importance of WPT systems is first reported from the engineering point of view, followed by their uses in biomedical devices.
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Affiliation(s)
- Lida Kouhalvandi
- Department of Electrical and Electronics Engineering, Dogus University, Istanbul 34775, Turkey
| | - Serdar Ozoguz
- Department of Electronics and Communication Engineering, Istanbul Technical University, Istanbul 34467, Turkey
| | - Mohsen Koohestani
- Department of Electrical and Electronic Engineering, ESEO School of Engineering, 49107 Angers, France
- Institute of Electronics and Telecommunications of Rennes, University of Rennes 1, 35042 Rennes, France
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Ullah S, Zada M, Basir A, Yoo H. Wireless, Battery-Free, and Fully Implantable Micro-Coil System for 7 T Brain MRI. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2022; 16:430-441. [PMID: 35657838 DOI: 10.1109/tbcas.2022.3179839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
An elegant solution for the concurrent transmission of data and power is essential for implantable wireless magnetic resonance imaging (MRI). This paper presents a self-tuned open interior microcoil (MC) antenna with three useful operating bands of 300 (7 T), 400, and 920 MHz, for blood vessel imaging, data telemetry, and efficient wireless transmission of power, respectively. The proposed open interior MC antenna contains two mirrorlike arms with diameters and lengths of 2.4 mm and 9.8 mm, respectively, to avoid blood flow blockage. To wirelessly show LED glow on a saline based phantom, the MC was fabricated on a flexible polyimide material and combined with a miniaturized rectifier and a micro-LED. Using a path gain, the power transfer efficiency (PTE) of the MC rotation was also analyzed. Additionally, the PTE was calculated for a range of distances between 25 and 60 mm, and a -27.1 dB PTE attained at a distance of of 30 mm. Based on the recommendations of the International Commission on Non-Ionizing Radiation Protection for human brain safety when exposed to radio-frequencies from external transmitter, a specific absorption rate analysis was analyzed. Measurements of the s-parameters were noted using a saline solution and blood vessel model to imitate a realistic human head. They were found to correlate reasonably with the simulated results.
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Pokharel RK, Barakat A, Alshhawy S, Yoshitomi K, Sarris C. Wireless power transfer system rigid to tissue characteristics using metamaterial inspired geometry for biomedical implant applications. Sci Rep 2021; 11:5868. [PMID: 33712654 PMCID: PMC7955087 DOI: 10.1038/s41598-021-84333-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/15/2021] [Indexed: 11/11/2022] Open
Abstract
Conventional resonant inductive coupling wireless power transfer (WPT) systems encounter performance degradation while energizing biomedical implants. This degradation results from the dielectric and conductive characteristics of the tissue, which cause increased radiation and conduction losses, respectively. Moreover, the proximity of a resonator to the high permittivity tissue causes a change in its operating frequency if misalignment occurs. In this report, we propose a metamaterial inspired geometry with near-zero permeability property to overcome these mentioned problems. This metamaterial inspired geometry is stacked split ring resonator metamaterial fed by a driving inductive loop and acts as a WPT transmitter for an in-tissue implanted WPT receiver. The presented demonstrations have confirmed that the proposed metamaterial inspired WPT system outperforms the conventional one. Also, the resonance frequency of the proposed metamaterial inspired TX is negligibly affected by the tissue characteristics, which is of great interest from the design and operation prospects. Furthermore, the proposed WPT system can be used with more than twice the input power of the conventional one while complying with the safety regulations of electromagnetic waves exposure.
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Affiliation(s)
- Ramesh K Pokharel
- Graduate School of Information Science and Electrical Engineering, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Adel Barakat
- Graduate School of Information Science and Electrical Engineering, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan.
| | - Shimaa Alshhawy
- Graduate School of Information Science and Electrical Engineering, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Kuniaki Yoshitomi
- Graduate School of Information Science and Electrical Engineering, Kyushu University, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Costas Sarris
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, M5S 3G4, Canada
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Abstract
Wireless power transmission (WPT) is a critical technology that provides an alternative for wireless power and communication with implantable medical devices (IMDs). This article provides a study concentrating on popular WPT techniques for IMDs including inductive coupling, microwave, ultrasound, and hybrid wireless power transmission (HWPT) systems. Moreover, an overview of the major works is analyzed with a comparison of the symmetric and asymmetric design elements, operating frequency, distance, efficiency, and harvested power. In general, with respect to the operating frequency, it is concluded that the ultrasound-based and inductive-based WPTs have a low operating frequency of less than 50 MHz, whereas the microwave-based WPT works at a higher frequency. Moreover, it can be seen that most of the implanted receiver’s dimension is less than 30 mm for all the WPT-based methods. Furthermore, the HWPT system has a larger receiver size compared to the other methods used. In terms of efficiency, the maximum power transfer efficiency is conducted via inductive-based WPT at 95%, compared to the achievable frequencies of 78%, 50%, and 17% for microwave-based, ultrasound-based, and hybrid WPT, respectively. In general, the inductive coupling tactic is mostly employed for transmission of energy to neuro-stimulators, and the ultrasonic method is used for deep-seated implants.
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Khan SR, Pavuluri SK, Cummins G, Desmulliez MPY. Wireless Power Transfer Techniques for Implantable Medical Devices: A Review. SENSORS (BASEL, SWITZERLAND) 2020; 20:E3487. [PMID: 32575663 PMCID: PMC7349694 DOI: 10.3390/s20123487] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 06/09/2020] [Accepted: 06/18/2020] [Indexed: 12/01/2022]
Abstract
Wireless power transfer (WPT) systems have become increasingly suitable solutions for the electrical powering of advanced multifunctional micro-electronic devices such as those found in current biomedical implants. The design and implementation of high power transfer efficiency WPT systems are, however, challenging. The size of the WPT system, the separation distance between the outside environment and location of the implanted medical device inside the body, the operating frequency and tissue safety due to power dissipation are key parameters to consider in the design of WPT systems. This article provides a systematic review of the wide range of WPT systems that have been investigated over the last two decades to improve overall system performance. The various strategies implemented to transfer wireless power in implantable medical devices (IMDs) were reviewed, which includes capacitive coupling, inductive coupling, magnetic resonance coupling and, more recently, acoustic and optical powering methods. The strengths and limitations of all these techniques are benchmarked against each other and particular emphasis is placed on comparing the implanted receiver size, the WPT distance, power transfer efficiency and tissue safety presented by the resulting systems. Necessary improvements and trends of each WPT techniques are also indicated per specific IMD.
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Affiliation(s)
- Sadeque Reza Khan
- Institute of Sensors, Signals, and Systems, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK; (S.K.P.); (M.P.Y.D.)
| | - Sumanth Kumar Pavuluri
- Institute of Sensors, Signals, and Systems, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK; (S.K.P.); (M.P.Y.D.)
| | - Gerard Cummins
- School of Engineering, University of Birmingham, Birmingham B15 2TT, UK;
| | - Marc P. Y. Desmulliez
- Institute of Sensors, Signals, and Systems, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK; (S.K.P.); (M.P.Y.D.)
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Design and Implementation of a Wireless Charging-Based Cardiac Monitoring System Focused on Temperature Reduction and Robust Power Transfer Efficiency. ENERGIES 2020. [DOI: 10.3390/en13041008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Wireless power transfer systems are increasingly used as a means of charging implantable medical devices. However, the heat or thermal radiation from the wireless power transfer system can be harmful to biological tissue. In this research, we designed and implemented a wireless power transfer system-based implantable medical device with low thermal radiation, achieving 44.5% coil-to-coil efficiency. To suppress thermal radiation from the transmitting coil during charging, we minimized the ESR value of the transmitting coil. To increase power transfer efficiency, a ferrite film was applied on the receiving part. Based on analyses, we fabricated a cardiac monitoring system with dimensions of 17 × 24 × 8 mm3 and implanted it in a rat. We confirmed that the temperature of the wireless charging device increased by only 2 °C during the 70 min charging, which makes it safe enough to use as an implantable medical device charging system.
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Optimal Position of the Intermediate Coils in a Magnetic Coupled Resonant Wireless Power Transfer System. ENERGIES 2019. [DOI: 10.3390/en12203991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Coaxial coil topology is used as the transfer medium in traditional MCR-WPT (Magnetic Coupled Resonant Wireless Power Transfer) systems to improve the transfer characteristics. The intermediate coils are added to extend the transmission distance, whose positions are critical. This paper focuses on the optimal intermediate coil positions for an MCR-WPT system with four coaxial planar circular spiral coils. By modeling the MCR-WPT system, the mathematical expression of the self-inductance and the mutual inductance are used to calculate the load power of the MCR-WPT system, which is composed of four planar circular spiral coaxial coils, and using MATLAB. The optimal distance ratio between the adjacent coils for maximizing the power of load is proposed. Furthermore, the experiments are implemented from the network analyzer and the experimental platform. In the platform, the load power is measured at the different intermediate coil positions, and the optimal position at which the load power is maximized is found. Both experimental results obtained by the network analyzer and the experimental platform have validated the theoretical and simulation results and provided the correctness of the suggested ratios.
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Evaluation of Specific Absorption Rate in Three-Layered Tissue Model at 13.56 MHz and 40.68 MHz for Inductively Powered Biomedical Implants. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9061125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This paper presents an optimized 3-coil inductive wireless power transfer (WPT) system at 13.56 MHz and 40.68 MHz to show and compare the specific absorption rate (SAR) effects on human tissue. This work also substantiates the effects of perfect alignment, lateral and/or angular misalignments on the power transfer efficiency (PTE) of the proposed WPT system. Additionally, the impacts of different tissue composition, input power and coil shape on the SAR are analyzed. The distance between the external and implantable coils is 10 mm. The results have been verified through simulations and measurements. The simulated results show that the SAR of the system at 40.68 MHz had crossed the limit designated by the Federal Communications Commission and hence, it is unsafe and causes tissue damage. Measurement results of the system in air medium show that the optimized printed circuit board coils at 13.56 MHz achieved a PTE of 41.7% whereas PTE waned to 18.2% and 15.4% at 10 mm of lateral misalignment and 60° of angular misalignment respectively. The PTE of a combination of 10 mm lateral misalignment and 60° angular misalignment is 21%. To analyze in a real-environment, a boneless pork sample with 10 mm of thickness is placed as a medium between the external and implantable coils. At perfect alignment, the PTE through pork sample is 30.8%. A RF power generator operating at 13.56 MHz provides 1 W input power to the external coil and the power delivered to load through the air and tissue mediums are 347 mW and 266 mW respectively.
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