Passive RF Backscattering Sensor for Intracranial Pressure Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of RF technology in biomedical applications is limited due to its high adsorption in aqueous materials, leading to inefficiency and safety concerns, such as unwanted temperature rises, especially when powering devices implanted inside the brain, where neurons are sensitive to temperature changes.
Innovation Solution
A fully-passive sensor system that uses RF backscattering without a battery, employing miniaturized MEMS technology and biotelemetry to measure pressure, allowing for wireless, battery-free operation and integration within the body, overcoming previous limitations in ICP monitoring systems and wireless technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If RF technology is used to power implanted devices, then wireless power transfer is achieved, but temperature rise in tissues occurs due to high adsorption of RF waves in aqueous materials
Solution Approach 1:
The patent extracts and removes the battery and active electronics from the implanted device, creating a fully passive sensor that contains no power source. This eliminates the need for RF power transfer entirely, thereby resolving the temperature rise issue caused by RF absorption in tissues while maintaining wireless operation capability
Solution Approach 2:
The patent replaces the electromagnetic (RF) power transfer system with a purely passive electromagnetic backscattering system. Instead of using RF waves to power active electronics, the system uses RF waves to modulate the impedance of passive components (varactor diodes) that reflect the waves back, substituting active power consumption with passive impedance modulation
2Ease of operation
If RF waves are used for wireless communication in biomedical applications, then wireless operation is achieved, but safety concerns arise due to unwanted temperature rise in sensitive areas like the brain
Solution Approach 1:
The patent removes all active electronic components and batteries from the implanted device, creating a fully passive sensor system. This extraction eliminates RF power transfer requirements, thereby maintaining wireless operation capability while removing the harmful thermal effects on temperature-sensitive neural tissue
Solution Approach 2:
The passive sensor system uses the incident RF waves themselves to modulate its impedance and encode measurement data, rather than requiring separate power and communication channels. The RF waves passively interact with the sensor's impedance-modulating components, enabling wireless data transmission without active power consumption or harmful heating
3Measurement precision
If active electronics and batteries are used in implanted pressure sensors, then sensing functionality is achieved, but device complexity and safety risks increase
Solution Approach 1:
The patent extracts and removes batteries and active electronic components from the implanted device, retaining only passive sensing elements (interdigitated electrodes, varactor diodes, and RF components). This simplifies the device structure while maintaining pressure sensing capability through passive impedance modulation
Solution Approach 2:
The patent uses pressure-induced changes in the physical state of the dielectric material between interdigitated electrodes to modulate the impedance of passive RF components. Pressure changes alter the capacitance and resonant frequency of the sensor, enabling measurement without active electronics or batteries
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 safe and efficient wireless pressure measurement within the body, including the brain, by utilizing RF backscattering for biotelemetry, reducing the risk of temperature rises and providing a concealed, battery-free solution for pressure sensing.
Implementation Method 1
A fully-passive sensor system that uses RF backscattering without a battery, employing miniaturized MEMS technology and biotelemetry to measure pressure
Data Source
AI summary
Fully-passive sensor systems that receive an input electromagnetic signal and return an output electromagnetic signal are described. The sensor systems can be used to measure pressure in biological or non-biological systems.