An Efficient Adaptive Antenna-Impedance Tuning Unit Designed for Wireless Pacemaker Telemetry

Po, Francis Chan Wai; Foucauld, Emeric de; David, Jean-Baptiste; Delavaud, C.; Ciais, P.

doi:10.5772/23602

Cited by 2 publications

(4 citation statements)

References 21 publications

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“…Chan Wai Po et al developed a method of calculating complex antenna impedance based on detected voltage on capacitors, and using the calculated impedance to determine and set tunable reactive components in a matching network [ 31 , 80 , 89 , 93 ]. Implementations included MEMS variable inductors, switched capacitor networks, and varactors.…”

Section: Implementations Of Adaptive Transcutaneous Systemsmentioning

confidence: 99%

“…Tuning power requirements are not provided, but it is proposed that the method reduces power requirements due to reduced tuning time. The method is applicable to both the transmitter and receiver, stated as the first system able to match both in a single process [ 31 ]. The transmit antenna impedance is matched to a power amplifier, while the receive antenna impedance is matched to a low noise amplifier.…”

Section: Implementations Of Adaptive Transcutaneous Systemsmentioning

confidence: 99%

“…Changes in the environment directly affect the performance and safety of a transcutaneous system, through effects on impedance and field characteristics. Impedance changes can reduce power transfer at the transmitter and receiver, as well as degrading efficiency if the impedance deviates from an optimal load or if there is increased absorption in tissue [ 31 , 32 , 33 ]. The degradation in power transfer and efficiency can lead to other problems in the system: Power reflections at the transmitter can damage the system, while reduced power delivery to the receiver can cause interruptions in function, and excess power delivery to the receiver could damage receiver circuitry or lead to tissue heating and safety concerns [ 34 , 35 , 36 , 37 , 38 ].…”

Section: Introductionmentioning

confidence: 99%

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Adaptive Transcutaneous Power Transfer to Implantable Devices: A State of the Art Review

Bocan

Sejdić

2016

Sensors

101

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Wireless energy transfer is a broad research area that has recently become applicable to implantable medical devices. Wireless powering of and communication with implanted devices is possible through wireless transcutaneous energy transfer. However, designing wireless transcutaneous systems is complicated due to the variability of the environment. The focus of this review is on strategies to sense and adapt to environmental variations in wireless transcutaneous systems. Adaptive systems provide the ability to maintain performance in the face of both unpredictability (variation from expected parameters) and variability (changes over time). Current strategies in adaptive (or tunable) systems include sensing relevant metrics to evaluate the function of the system in its environment and adjusting control parameters according to sensed values through the use of tunable components. Some challenges of applying adaptive designs to implantable devices are challenges common to all implantable devices, including size and power reduction on the implant, efficiency of power transfer and safety related to energy absorption in tissue. Challenges specifically associated with adaptation include choosing relevant and accessible parameters to sense and adjust, minimizing the tuning time and complexity of control, utilizing feedback from the implanted device and coordinating adaptation at the transmitter and receiver.

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Section: Implementations Of Adaptive Transcutaneous Systemsmentioning

confidence: 99%

Section: Implementations Of Adaptive Transcutaneous Systemsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Adaptive Transcutaneous Power Transfer to Implantable Devices: A State of the Art Review

Bocan

Sejdić

2016

Sensors

101

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“…A significant amount of work has been done to design RF antennas for implantable devices. A loop antenna was proposed to work at MICS band and embedded inside the header of the pacemaker [7]. A microstrip antenna was proposed to be attached to the pacemaker case but this adds extra thickness to the pacemaker profile [8].…”

Section: Introductionmentioning

confidence: 99%

Feasibility Study of Using the Housing Cases of Implantable Devices as Antennas

et al. 2016

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A novel antenna design for implantable pacemakers is proposed. The housing of a pacemaker is utilized as an antenna to cover both the 402-405 MHz Medical Implant Communication Service band and the 433-MHz Industrial, Scientific and Medical band. This is achieved by exploiting radiating characteristic current modes of the housing case. These modes are excited using a capacitive coupling element with the help of a matching circuit. The radiation pattern of this antenna is optimized to be in a desirable direction away from the body (off-body direction). The ability of the proposed antenna for communications is demonstrated using a transceiver and a base station at 433 MHz. A communication range of 1 m is established when a transmitter with the proposed antenna is implanted in a rabbit and the power fed by the transceiver to the antenna is 25 µW. A longer range of up to 19 m can be established with the maximum allowable transmit power within the safety limits. Furthermore, the far field wireless power transfer through the proposed antenna is investigated by experiment. A received power of up to 22.38 µW by the proposed antenna is demonstrated when an equivalent isotropically radiated power of 140 mW is transmitted 1 m away from a transmitting antenna. From the same transmitting antenna in the same distance, a power of 4 mW can be received when the transmit power is within safety limits. This power can be used to recharge a small battery or a capacitor, which can potentially cover the communication power consumption of the pacemaker and hence extend the life span of the primary battery.INDEX TERMS Housing antenna, MICS band antenna, pacemaker.

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An Efficient Adaptive Antenna-Impedance Tuning Unit Designed for Wireless Pacemaker Telemetry

Cited by 2 publications

References 21 publications

Adaptive Transcutaneous Power Transfer to Implantable Devices: A State of the Art Review

Adaptive Transcutaneous Power Transfer to Implantable Devices: A State of the Art Review

Feasibility Study of Using the Housing Cases of Implantable Devices as Antennas

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