Passive Wireless Pressure Sensor Using Compressible Dielectric
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Solution Overview
Problem
Existing physiological pressure monitoring technologies face challenges due to tethered solutions causing patient discomfort and risk of infection, and wireless solutions requiring large sizes and active circuitry, which limits their scalability and accuracy.
Innovation Solution
A passive wireless pressure sensor using a resonant circuit with inductive conductors separated by a compressible micro-structured elastomeric dielectric layer, which changes capacitance in response to pressure, allowing for continuous and scalable monitoring by altering the resonant frequency detectable via external energy fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tethered solutions are used for continuous monitoring, then monitoring reliability is improved, but patient comfort deteriorates and infection risk increases
Solution Approach 1:
The patent extracts the monitoring function from the tethered system by implanting a miniaturized sensor that wirelessly transmits data, separating the sensing function from the external monitoring equipment. This eliminates the physical connection that causes discomfort and infection risk while maintaining continuous monitoring capability
Solution Approach 2:
The patent replaces the mechanical tethered connection with a wireless electromagnetic communication system. The implanted sensor uses radio frequency transmission to communicate with external devices, eliminating the need for physical cables and connections that cause patient discomfort and infection
2Ease of operation
If wireless solutions with batteries and active circuitry are used, then wireless monitoring is achieved, but device size increases
Solution Approach 1:
The patent employs a passive sensor design that harvests energy from the surrounding electromagnetic environment or uses piezoelectric materials to generate energy from mechanical stress. This self-powered approach eliminates the need for batteries and active circuitry, dramatically reducing device size while maintaining wireless functionality
Solution Approach 2:
The patent utilizes piezoelectric materials that generate electrical charge in response to mechanical stress or vibration from pressure changes. This mechanical-to-electrical energy conversion provides the necessary power for wireless transmission without requiring batteries, enabling miniaturization of the sensor device
3Volume of moving object
If passive strategies are used, then device size is reduced, but detection precision deteriorates due to self-resonant frequency interference
Solution Approach 1:
The patent changes the operating frequency parameter to be significantly different from the self-resonant frequency of the readout circuitry. By operating at a frequency where interference effects are minimized, the sensor achieves both miniaturization and maintained detection precision
Solution Approach 2:
The patent introduces a matching network or impedance transformation circuit as an intermediary between the passive sensor and the readout system. This intermediary component optimizes signal transfer and minimizes the impact of self-resonant frequency interference, enabling accurate pressure detection in a miniaturized passive device
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
Enables continuous, accurate, and scalable monitoring of physiological pressure with smaller sensor sizes, operating at GHz frequencies, and mitigates interference issues, allowing for real-time monitoring of intracranial pressure and other physiological parameters.
Implementation Method 1
a compressible dielectric that supports the inductive conductors and that compresses and expands in response to changes in pressure
Implementation Method 2
The resonant circuit exhibits a first resonant frequency in response to an external energy field in the first state, with the first resonant frequency being based upon the first pressure
Implementation Method 3
Energy from the external energy field is used for wirelessly detecting pressure applied to the compressible dielectric by operating the resonant circuit respective states in which the resonant circuit exhibits different resonance in response to different pressures applied in each state
Implementation Method 4
The first and second inductive coils receive wireless energy, and the first and second inductive coils use the wireless energy to exhibit a resonant frequency
Data Source
AI summary
Aspects of the present disclosure are directed to pressure sensing. As may be implemented in accordance with one or more embodiments, an external energy field is applied to a resonant circuit having inductive conductors separated by a compressible dielectric, for wirelessly detecting pressure. Specifically, the resonant circuit is responsive to the energy field and applied pressures by operating in respective states exhibiting different resonant frequencies that are based upon pressure-related compression of the compressible dielectric. These resonant frequencies, or a change in the resonant frequencies, can be used as an indication of the pressure.