Self-Capacitance Wireless Power Transfer via Conductive Substrate

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Solution Overview

Problem

Existing wireless power transfer systems face inefficiencies and limitations, such as energy interference, large antenna sizes, orientation dependencies, and signal decay with distance, making them unsuitable for reliable power delivery to implantable and wearable devices.

Innovation Solution

A self-capacitance based wireless power transfer system that utilizes capacitively coupled power sources and energy harvesting devices, leveraging the intrinsic self-capacitance of electrically isolated bodies to provide efficient power delivery through a substrate, which scales linearly with dimensions and is robust to alignment artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If RF-based wireless power transfer is used, then power can be delivered wirelessly, but most energy is radiated to air causing interference and requiring large antenna sizes

Engineering Contradiction:

Improveenergy radiation lossVSAvoidantenna size

Core Design Contradiction:

Loss of energyVSArea of stationary object

Solution Approach 1:

The patent introduces a conductive substrate as an intermediary medium between the transmitter and receiver. The substrate guides electromagnetic energy directly to the target device rather than radiating through air, eliminating the need for large antennas and reducing energy loss to the surrounding environment.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional RF electromagnetic radiation mechanisms with a guided wave approach using conductive substrates. This substitution changes the fundamental mechanism from volumetric RF radiation to surface-guided energy transfer, improving efficiency and reducing antenna size requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If optical-based wireless power transfer is used, then power can be delivered wirelessly, but the system requires high optical power and proper orientation to light

Engineering Contradiction:

Improvepower delivery capabilityVSAvoidorientation requirement

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

The patent replaces optical-based wireless power transfer with electromagnetic wave guidance through conductive substrates. This eliminates the need for precise orientation alignment required by optical systems, as the substrate naturally guides the energy to the receiver regardless of angular positioning.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Power

If ultrasound-based wireless power transfer is used, then power can be delivered wirelessly, but signal decay increases exponentially with distance and frequency

Engineering Contradiction:

Improvepower delivery capabilityVSAvoidsignal decay

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent replaces ultrasound-based power transfer with electromagnetic wave guidance through conductive substrates. This substitution eliminates the exponential signal decay characteristic of ultrasound, as electromagnetic waves on conductive substrates experience much lower attenuation over distance and frequency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Power

If known WPT techniques are used, then power can be delivered wirelessly, but there is interference with external devices and limited scalability

Engineering Contradiction:

Improvepower delivery capabilityVSAvoidinterference with external devices

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The conductive substrate acts as a confined transmission medium that directs electromagnetic energy along its surface, preventing radiation into the surrounding environment. This intermediary structure eliminates interference with external RF and ultrasound devices while maintaining wireless power delivery capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 achieves high power transfer efficiency and scalability, outperforming conventional methods, particularly for powering distances and transducer form-factors, and demonstrates broad-band capabilities with minimal frequency adjustments, suitable for implantable and wearable devices.

Implementation Method 1

The power source and the energy harvesting device are configured to be capacitively coupled to a self-capacitive body

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

leveraging the intrinsic self-capacitance of electrically isolated bodies to provide efficient power delivery through a substrate

Methodology Applied

Scientific EffectSelf-capacitance: Capacitance

Data Source

PatentUS11611236B2Methods and apparatus for wireless power delivery and remote sensing using self-capacitances

Publication Date: 2023.03.21 WASHINGTON UNIV IN SAINT LOUIS

AI summary

A self-capacitance based remote power delivery device includes a power source, an energy harvesting device, and a substrate. The power source and the energy harvesting device are configured to be capacitively coupled to a self-capacitive body. The substrate is configured to be capacitively coupled to a portion of the self-capacitive body in contact with the substrate.