Wearable Bio-Electromagnetic Sensor Non-Contact Impedance
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Solution Overview
Problem
Existing bioimpedance monitoring devices are sensitive to movement and require galvanic contact, making them unsuitable for continuous monitoring of cardiovascular and respiratory parameters, as they struggle to maintain contact on moving body parts like the arm or wrist.
Innovation Solution
A wearable bio-electromagnetic sensor device that uses a toroidal magnet with a convex core shape to induce an electromagnetic field within the body, allowing for non-contact measurement of electrical impedance changes associated with blood flow, breathing, and heart activity, using a combination of inductive and capacitive components to process signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If galvanic contact electrodes are used for bioimpedance measurement, then measurement precision is improved, but reliability deteriorates due to contact maintenance issues during movement
Solution Approach 1:
The patent replaces the mechanical galvanic contact system with an electromagnetic induction system. Instead of using physical electrodes that require direct skin contact, the invention uses a coil to generate a magnetic field that induces currents in the body tissue, measuring bioimpedance through electromagnetic coupling rather than direct electrical contact. This eliminates the contact maintenance problem while preserving measurement capability.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the measurement device and the body tissue. The coil generates a magnetic field that penetrates the tissue, and the changing impedance of the tissue modifies this field, which is then detected by the coil. This intermediary approach allows measurement without direct galvanic contact, solving the reliability issue while maintaining precision.
2Reliability
If non-contact inductive coupling is used for bioimpedance measurement, then reliability is improved by avoiding contact issues, but measurement precision deteriorates due to signal weakness
Solution Approach 1:
The patent employs periodic excitation by driving the coil with an alternating current at a specific frequency. This periodic magnetic field induces corresponding periodic currents in the body tissue, and the bioimpedance changes modulate this periodic signal. By using periodic action, the weak inductive coupling signal is transformed into a detectable modulated waveform that can be precisely measured despite the non-contact nature of the coupling.
Solution Approach 2:
The patent optimizes the measurement by changing the frequency parameter of the excitation signal. By selecting an appropriate frequency for the alternating current driving the coil, the system maximizes the induced current in the tissue and the resulting signal strength. This parameter optimization ensures that the non-contact measurement maintains sufficient precision for accurate bioimpedance detection.
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, non-invasive monitoring of hemodynamic parameters like blood pressure, heart rate, and oxygen content without the need for galvanic contact, providing accurate and stable readings even on moving body parts.
Implementation Method 1
an electromagnetic interface for transforming the electrical current into an electromagnetic field to induce alternating current within a portion of the body
Implementation Method 2
a toroidal magnet is introduced a core shape of which follows said convex surface
Data Source
AI summary
A wearable bio-electromagnetic sensor comprises an electronic unit containing a means for generating electrical current, and an electromagnetic interface for transforming the generated electrical current into an electromagnetic field applied to a vascularized body tissue. Next, the wearable bio-electromagnetic sensor contains a means for analog signal processing an electrical response of cardiopulmonary system to the applied electromagnetic field. After analog processing of said electrical response, a digital post-processing of digitized electrical response takes place in a means for digital signal processing, embedded into said electronic unit of the wearable bio-electromagnetic sensor. As a result of analog and digital signal processing, an information is extracted, which makes possible medical diagnosing of both, pulmonary and cardiovascular system, separately or simultaneously. The used work principle is following: the applied electromagnetic field induces electrical current inside the body tissue, electrical impedance to which changes correspondingly to breathing and heart beating. Said electrical impedance of varies during every breathing cycle correspondingly to oxygen transporting through arteries and oxygen uptake by capillaries, also due to biomechanical enlargement and narrowing of arteries correspondingly to blood pressure variations.