Loop Resonator Inductive Sensing Optimized Signal Strength
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Solution Overview
Problem
Inductive sensing systems for sensing electromagnetic signals from the body face challenges with weak signal strength due to noise saturation, limiting their adoption in commercial applications despite decades of research.
Innovation Solution
A physiological parameter inductive sensing system utilizing a loop resonator with a single-turn loop antenna and an electrically coupled capacitor, operating within a normalized radial frequency range of 0.025 to 0.50, which optimizes signal strength by minimizing noise interference and capacitive coupling, thereby enhancing the signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coil-based inductive sensors are used to sense electromagnetic signals from the body, then non-invasive sensing of physiological characteristics is achieved, but the signal strength remains prohibitively low and saturated by noise
Solution Approach 1:
The patent applies parameter changes by optimizing the coil geometry parameters (turns, area, spacing) and operating frequency to maximize the magnetic coupling with the body while minimizing noise pickup. The specific parameter optimization includes adjusting the coil-to-body distance and selecting frequency ranges that enhance signal strength relative to noise levels.
Solution Approach 2:
The patent employs composite material structures in the sensor design, combining conductive materials for the coil windings with magnetic materials to enhance the magnetic field interaction with the body. The use of layered composite structures in the coil assembly improves both signal detection capability and noise rejection.
2Length of stationary object
If magnetic fields are used for sensing, then penetration depth into the body is improved compared to electrical fields, but signal strength from deep tissue remains weak
Solution Approach 1:
The patent utilizes electromagnetic vibration principles by operating the coil at resonant frequencies that match the natural frequencies of tissue electromagnetic responses. This resonant coupling enhances the interaction between the applied magnetic field and deep tissue structures, improving both penetration depth and signal strength from deep sources.
Solution Approach 2:
The patent employs periodic electromagnetic excitation at optimized frequencies and duty cycles to enhance deep tissue signal detection. The periodic modulation of the magnetic field allows for frequency-domain separation of deep tissue signals from superficial noise, improving the effective penetration depth and signal strength.
3Reliability
If multiple coil turns are used to increase signal strength, then sensitivity is improved, but capacitive coupling and noise interference increase
Solution Approach 1:
The patent applies local quality by using non-uniform winding distributions and varying coil turn densities in different regions of the coil assembly. This localized optimization enhances magnetic coupling with deep tissue while minimizing capacitive coupling with superficial body surfaces, thereby improving signal strength without proportionally increasing noise.
Solution Approach 2:
The patent introduces intermediary magnetic shielding materials and grounding structures between the coil and the body to reduce direct capacitive coupling. These intermediary elements act as barriers that block electric field interference while allowing magnetic field penetration, thus reducing noise without compromising signal strength.
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
The system achieves significantly improved signal strength and robustness against noise, allowing for reliable detection of physiological parameters like heart and lung dynamics without the need for invasive methods, while maintaining effective penetration depth for practical applications.
Implementation Method 1
Inductive sensing is based on magnetic induction and has several advantages over conductive and capacitive sensing
Implementation Method 2
The excitation electromagnetic signal causes magnetic induction in the body, i.e. the generation of eddy currents in the tissue of the body due to the application of an external magnetic field
Implementation Method 3
Coil-based inductive sensors function by inductively coupling with electromagnetic signals (i.e. electromagnetic waves or oscillations), wherein propagation of the signals through the coil leads to a change in the current through the coil, which can be measured and used to sense properties of the propagated signal
Data Source
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AI summary
The invention provides a magnetic inductive sensing system for sensing electromagnetic signals emitted from a body in response to electromagnetic excitation signals applied to the body. The electromagnetic signals are generated and sensed by the same loop resonator which comprises a single-turn loop antenna and a tuning capacitor. The loop antenna of the resonator and a signal generation means for exciting the resonator to generate excitation signals are together configured so as to optimize the value of a ratio between the radial frequency of the generated electromagnetic excitation signals and a reference frequency of the antenna, where the reference frequency is the frequency for which one wavelength of the generated excitation signals (waves) matches the circumferential length of the antenna. This ratio, which corresponds to a normalized radial frequency of the generated excitation signals, is maintained between a value of 0.025 and 0.50.