Far Field Radiative Powering for Implantable Medical Devices
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Solution Overview
Problem
Current methods for powering implantable medical devices, such as inductive coupling, are limited by the need for close proximity and proper alignment, restricting patient mobility and efficiency due to reliance on near-field magnetic fields, which dissipate rapidly with distance.
Innovation Solution
The use of far-field radiative signals allows for wireless power transfer over greater distances using electrical fields, eliminating the need for onboard power storage and enabling miniaturization of devices, with multiple frequencies or transmitters increasing power transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If inductive coupling is used to power implantable medical devices, then power can be transferred wirelessly, but the coils must be relatively close and properly aligned, restricting patient mobility
Solution Approach 1:
The patent changes the fundamental parameter of electromagnetic field interaction from near-field inductive coupling to far-field radiative coupling. This allows power transfer over distances of several feet rather than requiring close proximity and alignment, thereby resolving the contradiction between wireless power transfer and patient mobility
2Loss of energy
If inductive coupling is used, then power can be transferred to the device, but efficiency decreases when coils are not aligned or oriented properly
Solution Approach 1:
The patent transitions from near-field magnetic coupling parameters to far-field radiative coupling parameters. The external transmitter uses a dipole or monopole antenna that radiates electromagnetic waves, and the implantable device uses a dipole antenna to receive these waves. This parameter change eliminates the alignment requirements inherent in inductive coupling, maintaining high efficiency regardless of orientation
3Device complexity
If far field radiative signals are used, then patient mobility is enhanced and device miniaturization is enabled, but multiple frequencies and transmitters are needed to increase power transfer efficiency
Solution Approach 1:
The patent segments the power transfer system into multiple frequency bands, with different transmitters operating at different frequencies (e.g., 900 MHz, 2.4 GHz). The implantable device contains multiple dipole antennas that can receive signals across these different frequency bands. This segmentation allows the system to overcome the limitation that a single frequency may not provide sufficient power transfer efficiency, while still enabling device miniaturization through far-field coupling
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
This approach enhances patient mobility and reduces complexity in implantation procedures, enabling effective treatment of various conditions by delivering electrical stimulation signals to targeted tissues without the constraints of near-field interactions.
Implementation Method 1
an external transmitter configured to transmit a first electromagnetic signal at a first frequency to a first implantable medical device and a second electromagnetic signal at a second frequency to a second implantable medical device
Implementation Method 2
configured to receive a first electromagnetic signal at a first frequency from an external transmitter and to charge a battery using the first electromagnetic signal
Data Source
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Figure 5
AI summary
A system includes a first implantable medical device configured to receive a first far field radiative signal at a first frequency from an external transmitter to charge a first charge storage device. The first implantable medical device includes a first therapy delivery unit powered by the first charge storage device. The first therapy delivery unit delivers a first therapy to a first target tissue of a patient. The system also includes a second implantable medical device configured to receive a second far field radiative signal at a second frequency from the external transmitter to charge a second charge storage device. The second implantable medical device includes a second therapy delivery unit powered by the second charge storage device. The second therapy delivery unit delivers a second therapy to a second target tissue of the patient.