Dual-Frequency Radar for Heartbeat Sensing Amid Respiration Interference
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Solution Overview
Problem
Traditional vital sign monitoring systems are intrusive, limit mobility, and suffer from poor heartbeat accuracy due to the larger dynamic range of respiration signals, and radar-based systems cause privacy concerns or require cumbersome setups.
Innovation Solution
A dual-frequency radar system using 2.45 GHz and 5.8 GHz carrier frequencies to simultaneously detect heartbeat and respiration signals, employing signal combining techniques to cancel out respiration contributions and enhance heartbeat signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If single frequency radar or FMCW radar is used to detect both respiration and heartbeat signals, then both signals can be detected simultaneously, but the heartbeat detection accuracy deteriorates due to the larger dynamic range of respiration signals
Solution Approach 1:
The patent segments the detection process by using two different carrier frequencies (first and second frequencies). The first frequency is optimized for detecting respiration signals while the second frequency is optimized for detecting heartbeat signals. This segmentation allows each frequency to specialize in detecting one type of signal, thereby improving heartbeat detection accuracy while maintaining the ability to detect both signals simultaneously.
Solution Approach 2:
The patent applies local quality by assigning different properties to different frequencies used in the radar system. The first carrier frequency is selected with properties suitable for respiration detection (larger wavelength, better for larger dynamic range signals), while the second carrier frequency is selected with properties suitable for heartbeat detection (smaller wavelength, better for smaller amplitude signals). This localized optimization of frequency properties resolves the contradiction between detecting both signals and maintaining heartbeat accuracy.
2Measurement precision
If traditional vital sign monitoring systems with attached sensors are used, then accurate bio-signal measurement can be achieved, but patient mobility is limited and comfort is reduced
Solution Approach 1:
The patent replaces the mechanical contact-based sensor system with a radar-based electromagnetic wave system. Instead of using physical sensors that attach to the patient's body (mechanical system), the system uses radar waves to remotely detect bio-signals. This substitution eliminates the need for physical contact, thereby maintaining measurement accuracy while fully preserving patient mobility and comfort.
3Ease of operation
If remote radar-based monitoring is used to avoid contact, then patient comfort and mobility are maintained, but heartbeat signal detection accuracy deteriorates due to respiration signal interference
Solution Approach 1:
The patent segments the frequency spectrum into two distinct carrier frequencies for remote radar monitoring. By using the first frequency primarily for respiration detection and the second frequency primarily for heartbeat detection, the system maintains contactless operation (preserving comfort and mobility) while improving heartbeat detection accuracy through frequency-based signal separation.
Solution Approach 2:
The patent changes the parameter of carrier frequency to resolve the interference problem. By selecting specific values for the first and second carrier frequencies, the system optimizes each frequency for detecting specific bio-signals. This parameter change allows the system to maintain remote monitoring capabilities while significantly improving heartbeat signal detection accuracy by reducing respiration signal interference.
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 provides improved heartbeat signal quality for remote, contactless monitoring, enabling accurate diagnosis and health condition detection.
Implementation Method 1
at least one radar signal transmitter configured to transmit at least a first radar signal at a first carrier frequency and a second radar signal at a second carrier frequency; at least one signal receiver configured to receive at least one radar return signal
Data Source
AI summary
An apparatus (10) for performing a remote measurement of a bio-signal of a subject, the device comprising: at least one radar signal transmitter (14) configured to transmit at least a first radar signal at a first carrier frequency and a second radar signal at a second carrier frequency; at least one signal receiver (16) configured to receive at least one radar return signal; detection circuitry (18) coupled to the signal receiver, wherein the detection circuitry (18) is configured to produce at least one first detection signal for the first carrier frequency and at least one second detection signal for the second carrier frequency in response to receiving the at least one radar return signal at the signal receiver (16), wherein the first carrier frequency and the second carrier frequencies are such that the at least one first and/or the at least one second detection signals comprise a contribution from the bio-signal and a contribution from a further bio-signal and/or a background; and signal combining circuitry (20) configured to perform a signal combining process with the at least one first detection signal and the at least one second detection signal to produce at least one combined signal comprising an at least reduced contribution from the further bio-signal and/or background.