Resonant Antennas for Implantable Medical Device Power Transfer
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Solution Overview
Problem
Conventional wireless power transfer methods for implanted medical devices, such as ventricular assist devices (VADs), face inefficiencies and reliability issues due to distance and alignment variations between transmitter and receiver coils, leading to potential power drops that can compromise cardiac function.
Innovation Solution
A system with a transmitting antenna and a receiving antenna configured to maintain at least 40% power transfer efficiency, even at varying distances and alignments, using dynamic coupling and a controller to adjust power levels and ensure continuous operation of the implanted pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inductive coupling techniques are used for wireless power transfer, then power transfer is achieved through the patient's skin, but the magnetic coils require very close separation distance and have restrictions on misalignment, limiting practicality
Solution Approach 1:
The patent changes the operating parameters by using resonant frequency coupling instead of conventional inductive coupling. The transmitting and receiving coils are tuned to resonate at the same frequency, which fundamentally alters the power transfer mechanism. This resonance-based approach allows for much greater separation distances (over 1 meter) and tolerates misalignment between coils, directly resolving the contradiction between reliable power transfer and positioning flexibility.
Solution Approach 2:
The patent introduces an intermediary mechanism by using a relay resonator positioned between the external transmitter coil and the implanted receiver coil. This relay resonator acts as a mediator that extends the power transfer path, allowing the external coil to be positioned farther from the implanted device while maintaining effective power transfer. The relay resonator compensates for the distance and alignment issues, enabling practical use with greater positioning flexibility.
2Object-affected harmful factors
If wireless power transfer is implemented to eliminate percutaneous drivelines, then patient quality of life improves by reducing exit site infections, but power transfer efficiency decreases with distance and alignment variations
Solution Approach 1:
The patent employs dynamic power management control that continuously monitors the power transfer efficiency and adjusts operating parameters in real-time. The system dynamically tunes the resonant frequency of the coils and adjusts the power levels to compensate for variations in distance and alignment. This dynamic adaptation maintains high power transfer efficiency despite changes in the physical configuration, resolving the contradiction between eliminating drivelines and maintaining energy transfer efficiency.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors the actual power transfer efficiency and uses this information to adjust the transmitting and receiving coils' operating parameters. The feedback loop ensures that power transfer efficiency is maintained at acceptable levels by making real-time corrections to frequency and power settings, thereby enabling wireless power transfer without sacrificing energy efficiency.
3Adaptability or versatility
If power transfer distance is increased to accommodate patient movement and positioning, then coil alignment restrictions are relaxed, but power transfer efficiency is reduced
Solution Approach 1:
The patent utilizes resonant oscillation of the coils at a specific frequency to enhance power transfer over extended distances. By tuning both the external transmitter and implanted receiver coils to the same resonant frequency, the system creates a resonant coupling effect that amplifies the magnetic field interaction. This resonance mechanism maintains efficient power transfer even when coils are positioned over 1 meter apart or are slightly misaligned, directly addressing the contradiction between positioning adaptability and energy loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system ensures a stable power supply to the implanted pump, minimizing complications and adverse health consequences by maintaining sufficient power transfer regardless of changes in coil positioning or orientation, thus ensuring continuous cardiac support.
Implementation Method 1
The transmitting antenna is configured to transmit a second level of power through an outer skin surface of the patient
Implementation Method 2
The receiving antenna is configured to receive the second level of power and to transmit a third level of power to the housing
Data Source
AI summary
Systems, devices and methods are provided for supporting cardiac function. One system comprises an implantable intracardiac device comprising a motor and a pump, an external energy source and a transmitting resonator comprising a magnetic coil and configured to receive a first level of power from the external energy source and transmit a second level of power through an outer skin surface of the patient. The system further comprises a receiving resonator configured for implantation within the patient, comprising a magnetic coil and configured to transmit a third level of power to the motor within the implanted device. The third level of power is at least 40% of the first level of power, thereby ensuring that the pump will continuously pump blood through the heart at a sufficient rate regardless of any changes in the system, such as power loss due to transmission inefficiencies and/or changes in the relative positions between the transmitting and receiving coils.