Working frequency in wireless power transfer for implantable biomedical sensors

Mohamadi, Taghi

doi:10.1109/iceei.2011.6021545

Cited by 11 publications

(13 citation statements)

References 9 publications

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“…This can be provided when the switch current and voltage are kept in phase by adjusting the switching frequency (40), the duty cycle of the gate driver signal (41), the primary inductance (42,43), or the primary capacitance (44,45).…”

Section: Closed-loop Systemsmentioning

confidence: 99%

Prosthetic Power Supplies

Trigui

Mehri

Ammari

et al. 2015

Wiley Encyclopedia of Electrical and Electronics Engineering

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During the last few decades, implantable medical devices (IMDs) changed the landscape of modern medicine. Combining many technologies and employing smart medical devices within the human body, they allowed a continuous and automatic management of numerous health issues, such as pacemakers and implantable cardiac defibrillators, cochlear implants, bladder controllers, endoscopic capsules, nerve stimulators, lab‐on‐a‐chip, and artificial retinal prosthesis. Due to their continuously increasing potential, IMDs are getting more complex, thus requiring more energy to operate. Most of these advanced implantable devices are extracorporeally powered or battery charged through wireless power transfer (WPT) mechanisms. Following the basic principle of IMD power supplies, we introduce various power transfer techniques, and then focus on the inductive links and various methods to maximize the energy transferred to implantable devices and the calibration methods of these WPT techniques.

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Section: Closed-loop Systemsmentioning

confidence: 99%

Prosthetic Power Supplies

Trigui

Mehri

Ammari

et al. 2015

Wiley Encyclopedia of Electrical and Electronics Engineering

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“…III. UWB WAVEFORMS UWB impulses are characterized by an extremely wide bandwidth, good resolution range and by definition have a fractional bandwidth of 0.2 or a 10 dB bandwidth of 500 MHz [8].…”

Section: System Topologiesmentioning

confidence: 99%

UWB power propagation for bio-medical implanted devices

Ghafari

Brennan

Ghavami

2015

2015 17th International Conference on E-Health Networking, Application &Amp; Services (HealthCom)

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Abstract-This work presents a study of ultra wideband (UWB) technology to compute the energy transmission level as an electromagnetic impulse traveling from the transmitter antenna into the human body, and reaching the receiver antenna. The consideration is based on two center frequencies at 3.5 GHz which occupies 1 GHz bandwidth and at 6.1 GHz occupying 6 GHz bandwidth. A small discone antenna with gain of 1.8 dBi is employed as the transmitter antenna and a designed implantable patch antenna with gain of 4 dBi is also used as the receiver antenna. The distance between two antennas is 23.6 mm and the tissue attenuation has been considered for two layers including skin and fat with thickness of 2 mm and 9.6 mm respectively. The computation is accomplished for one way-link UWB radar system with respect to FCC regulation, UWB antenna characteristic and Biological tissue model focusing on attenuation affects. The attenuation is based on the response of the transmitted incident power to reflection, absorption and thickness of the human tissue including frequency-dependent parameters such as permittivity and conductivity. Computer simulation results demonstrate the power comparison for two center frequencies in terms of bandwidth and attenuation. Since the lower band of UWB is suitable for radiation into the human body due to the greater penetration of signals, the results indicate that despite the increasing frequency from 3.5 GHz to 6.1 GHz, there is only minor power variations at the receiver.

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“…Dissanayake et al 2009 [ 71 ] used closed loop frequency control system with a switched capacitor control method and power regulated for separations of 10 mm to 20 mm at 10 W. Mohamadi [ 72 ] changed the operating frequency by controlling the tuned capacitor on the primary side, according to the feedback signals. Shmilovitz et al [ 73 ] used a method where voltage regulation is based on hysteretic control of the implanted storage capacitor voltage.…”

Section: Automatic Frequency Controllermentioning

confidence: 99%

Automatic Frequency Controller for Power Amplifiers Used in Bio-Implanted Applications: Issues and Challenges

Hannan

Hussein

Mutashar

et al. 2014

Sensors

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With the development of communication technologies, the use of wireless systems in biomedical implanted devices has become very useful. Bio-implantable devices are electronic devices which are used for treatment and monitoring brain implants, pacemakers, cochlear implants, retinal implants and so on. The inductive coupling link is used to transmit power and data between the primary and secondary sides of the biomedical implanted system, in which efficient power amplifier is very much needed to ensure the best data transmission rates and low power losses. However, the efficiency of the implanted devices depends on the circuit design, controller, load variation, changes of radio frequency coil's mutual displacement and coupling coefficients. This paper provides a comprehensive survey on various power amplifier classes and their characteristics, efficiency and controller techniques that have been used in bio-implants. The automatic frequency controller used in biomedical implants such as gate drive switching control, closed loop power control, voltage controlled oscillator, capacitor control and microcontroller frequency control have been explained. Most of these techniques keep the resonance frequency stable in transcutaneous power transfer between the external coil and the coil implanted inside the body. Detailed information including carrier frequency, power efficiency, coils displacement, power consumption, supplied voltage and CMOS chip for the controllers techniques are investigated and summarized in the provided tables. From the rigorous review, it is observed that the existing automatic frequency controller technologies are more or less can capable of performing well in the implant devices; however, the systems are still not up to the mark. Accordingly, current challenges and problems of the typical automatic frequency controller techniques for power amplifiers are illustrated, with a brief suggestions and discussion section concerning the progress of implanted device research in the future. This review will hopefully lead to increasing efforts towards the development of low powered, highly efficient, high data rate and reliable automatic frequency controllers for implanted devices.

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Working frequency in wireless power transfer for implantable biomedical sensors

Cited by 11 publications

References 9 publications

Prosthetic Power Supplies

Prosthetic Power Supplies

UWB power propagation for bio-medical implanted devices

Automatic Frequency Controller for Power Amplifiers Used in Bio-Implanted Applications: Issues and Challenges

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