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Publication Number
US-12176725-B2
Publication Date
2024-12-24
Expiration Date
Abstract
Described herein are devices, systems, and methods for wireless power transfer utilizing a midfield source and implant. In one variation, a midfield source may be realized by a patterned metal plate composed of one of more subwavelength structures. These midfield sources may manipulate evanescent fields outside a material (e.g., tissue) to excite and control propagating fields inside the material (e.g., tissue) and thereby generate spatially confined and adaptive energy transport in the material (e.g., tissue). The energy may be received by an implanted device, which may be configured for one or more functions such as stimulation, sensing, or drug delivery.
Core Innovation
The disclosure provides a wireless midfield power transfer approach that uses a patterned midfield plate with subwavelength structures to manipulate evanescent fields outside tissue and excite propagating field modes within tissue. The excitation and field manipulation enable spatially confined energy delivery to a location in tissue that is associated with an implantable stimulation device, with dynamic focusing capabilities for spatially shifting a focal region. The system is described as delivering power to mm-scale implanted devices.
The disclosure states theoretical foundations for midfield power transfer efficiency and optimization using electromagnetic theory and coupled-mode or equivalent-optics formulations. It describes example transmitter/receiver architectures including a midfield source with a planar substrate and excitation ports, concepts related to metasurface/immersion-lens configurations, and adaptive phase/amplitude control. The implant receiver is described as an E-field based antenna with dielectric encapsulation and AC-DC conversion circuitry, along with sensing and stimulation modules and support for bidirectional wireless data/power transfer.
The focusing behavior is achieved using tuned coupler and excitation control, including amplitude/phase matching network concepts such as phase matching and amplitude detection with adaptive gain. It describes customizing midfield coupler geometry using imaging-derived tissue models and solving for current distributions to design patient-specific midfield plates, and it provides example phase/amplitude matching network concepts for port-based tuning based on measured received signal phases and amplitudes. Reported results and compliance statements include simulated and measured power transfer in porcine tissue and SAR safety assessment.
Claims Coverage
The independent claims cover a wireless powering system/apparatus that focuses wireless signals into tissue using a coupler with phase matching, and uses amplitude-based control to adjust variable gain based on signals received at the coupler. Across the independent claims, the inventive feature set includes four features.
Amplitude detector drives variable gain in proportion to detected amplitude
An amplitude detector electrically coupled to the coupler determines an amplitude of a signal received at the coupler, and a variable gain amplifier electrically coupled between the radio and the coupler amplifies a signal from the radio in proportion to the amplitude determined by the amplitude detector.
Coupler converts radio signals and focuses tissue energy at a location associated with an implantable stimulation device
A coupler electrically coupled to the radio converts signals from the radio to wireless signals and focuses the signals to a location in tissue associated with an implantable stimulation device.
Phase matching network with phase detector and phase shifter adjusts phase based on determined received phase
A phase matching network comprising a phase detector and a phase shifter electrically coupled to the coupler, where the phase detector determines a phase of a signal received at the coupler and the phase shifter adjusts a phase of a signal provided to and by the coupler based on the determined phase.
Tissue focusing within a wavelength as measured in air
The coupler focuses the signals to a location in tissue that is within a wavelength of the wireless signals as measured in air.
Overall, the claims focus on a coupler that converts and focuses wireless signals in tissue, a phase matching network that uses a phase detector and a phase shifter to adjust phase based on determined received phase, and an amplitude detector that sets a variable gain amplifier proportionally to detected amplitude.
Stated Advantages
Enables spatially confined energy delivery to mm-scale implanted devices by focusing wireless signals in tissue.
Provides dynamic focusing capability for spatially shifting a focal region.
Supports dynamic adaptive focusing via feedback using amplitude and phase control elements.
The disclosure includes SAR compliance and dynamic SAR safety assessment for safety in body/head absorbed power measurement.
Documented Applications
Cardiac pacing.
Deep brain stimulation.
Spinal cord and peripheral nerve stimulation.
Sleep apnea/tongue stimulation.
Wireless endoscopy.
Drug delivery.
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