Multiple-target vital sign detector and detection method using the same

Patent metadata

Field	Value
Publication number	US-11835618-B2
Application number	US-202017064707-A
Country	US
Kind code	B2
Filing date	Oct 7, 2020
Priority date	Oct 9, 2019
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

A multiple-target vital sign detector includes a self-injection-locked oscillator (SILO), a chirp up/down converter, a frequency demodulator and a multiple-target vital sign processor. The chirp up/down converter performs conversion from an oscillation signal generated by the SILO to a frequency-modulated continuous wave (FMCW) signal to detect an area and from a received FMCW signal reflected from the area to an injection signal, while the SILO is injected with the injection signal to enter a self-injection-locked state. The locations and vital signs of multiple subjects are extracted from the oscillation signal using the frequency demodulator and the multiple-target vital sign processor. The objective of using the SILO is to improve the sensitivity of the FMCW detection process so as to more effectively distinguish the vital signs of multiple subjects at different locations.

First claim

What is claimed is:

1. A multiple-target vital sign detector, comprising:
a self-injection-locked oscillator (SILO) configured to generate an oscillation signal;
a chirp up/down converter including a upconverting mixer, a transceiver antenna and a downconverting mixer, the upconverting mixer is electrically connected to the SILO and configured to convert the oscillation signal into a frequency-modulated continuous wave (FMCW) signal, the transceiver antenna is electrically connected to the upconverting mixer, configured to transmit the FMCW signal to an area as a transmitted signal and configured to receive a reflected signal from the area as a received FMCW signal, the downconverting mixer is electrically connected to the transceiver antenna and configured to convert the received FMCW signal into an injection signal, wherein the SILO is electrically connected to the downconverting mixer and configured to receive the injection signal to enter a self-injection-locked state;
a frequency demodulator electrically connected to the SILO and configured to frequency-demodulate the oscillation signal to produce a frequency-demodulated signal; and
a multiple-target vital sign processor electrically connected to the frequency demodulator and configured to sample and process the frequency-demodulated signal to construct a range-vital-Doppler map.

2. The multiple-target vital sign detector in accordance with claim 1 , wherein the chirp up/down converter further includes a chirp signal generator that is configured to output a chirp signal, the upconverting mixer is electrically connected to the chirp signal generator, configured to convert the oscillation signal into the FMCW signal by mixing the oscillation signal with the chirp signal, the downconverting mixer is electrically connected to the chirp signal generator, configured to convert the received FMCW signal into the injection signal by mixing the received FMCW signal with the chirp signal.

3. The multiple-target vital sign detector in accordance with claim 2 further comprising a first power splitter, wherein the first power splitter is electrically connected to the SILO and configured to split the oscillation signal into two parts, one part of the oscillation signal is configured to be delivered to the upconverting mixer, and the other part of the oscillation signal is configured to be delivered to the frequency demodulator.

4. The multiple-target vital sign detector in accordance with claim 3 , wherein the chirp up/down converter further includes a second power splitter that is electrically connected to the chirp signal generator and configured to split the chirp signal into two parts, one part of the chirp signal is configured to be delivered to the upconverting mixer, and the other part of the chirp signal is configured to be delivered to the downconverting mixer.

5. The multiple-target vital sign detector in accordance with claim 1 , wherein the multiple-target vital sign processor includes a range-Doppler map (RDM) creating module that is configured to sample and process the frequency-demodulated signal to create an RDM.

6. The multiple-target vital sign detector in accordance with claim 5 , wherein the multiple-target vital sign processor further includes a background subtraction module, an amplitude normalization module and a peak searching module, the background subtraction module is configured to eliminate a background of the RDM to create a background-subtracted RDM, the amplitude normalization module is configured to normalize the background-subtracted RDM in amplitude to create a normalized background-subtracted RDM, the peak searching module is configured to search for peaks above a certain threshold in the normalized background-subtracted RDM to construct a range-vital-Doppler map, wherein both range and vital sign frequency information are displayed simultaneously.

7. The multiple-target vital sign detector in accordance with claim 1 , wherein the transceiver antenna includes a transmit antenna and a receive antenna, the transmit antenna is electrically connected to the upconverting mixer and configured to transmit the FMCW signal from the upconverting mixer to the area as the transmitted signal, the receive antenna is electrically connected to the downconverting mixer and configured to receive the reflected signal from the area as the received FMCW signal and deliver the received FMCW signal to the downconverting mixer.

8. The multiple-target vital sign detector in accordance with claim 7 , wherein the receive antenna is a switched antenna array including a switch and a plurality of receive array antenna elements, the receive array antenna elements are configured to receive the reflected signal from the area as the received FMCW signal, the switch is electrically connected to the downconverting mixer and the receive array antenna elements and configured to switch one of the receive array antenna elements to couple to the downconverting mixer, the downconverting mixer is configured to convert the received FMCW signal into the injection signal, a phase shifter is electrically connected to the downconverting mixer and the SILO and configured to shift the phase of the injection signal by 0 or 90 degrees to produce a quadrature phase-shifted injection signal, the quadrature phase-shifted injection signal is configured to be injected into the SILO to make the SILO enter the self-injection-locked state.

9. The multiple-target vital sign detector in accordance with claim 8 , wherein the SILO is configured to operate in the self-injection-locked state to generate a quadrature phase-shifted oscillation signal, a first power splitter is configured to split the quadrature phase-shifted oscillation signal into two parts, one part of the quadrature phase-shifted oscillation signal is configured to be delivered to the upconverting mixer for conversion into the FMCW signal, and the other part of the quadrature phase-shifted oscillation signal is configured to be delivered to the frequency demodulator, the frequency demodulator is configured to frequency-demodulate the quadrature phase-shifted oscillation signal to produce a quadrature frequency-demodulated signal.

10. The multiple-target vital sign detector in accordance with claim 9 , wherein the multiple-target vital sign processor includes a range-Doppler map (RDM) creating module and an azimuth digital beamforming module, the RDM creating module is configured to sample and process the quadrature frequency-demodulated signal to create a plurality of RDMs corresponding to the receive array antenna elements, the azimuth digital beamforming module is coupled to the RDM creating module and configured to extract a range-azimuth map from the RDMs corresponding to the receive array antenna elements.

11. A detection method using a multiple-target vital sign detector, comprising:
generating an oscillation signal using a self-injection-locked oscillator (SILO);
performing conversion from the oscillation signal to an FMCW signal to detect an area and from a received FMCW signal reflected from the area to an injection signal using a chirp up/down converter, the chirp up/down converter includes a upconverting mixer, a transceiver antenna and a downconverting mixer, the upconverting mixer is electrically connected to the SILO and configured to convert the oscillation signal into the FMCW signal, the transceiver antenna is electrically connected to the upconverting mixer, configured to transmit the FMCW signal to the area as a transmitted signal and configured to receive a reflected signal from the area as the received FMCW signal, the downconverting mixer is electrically connected to the transceiver antenna and configured to convert t

Assignees

• National Sun Yat Sen University

Inventors

• Horng Tzyy-Sheng
• Wang fu-kang
• Su Wei-Chih
• Tang Mu-Cyun
• Arif Rezki El

Classifications

• G01S13/89 Primary

  for mapping or imaging · CPC title

• A61B5/05 Primary

  Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves (measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24) · CPC title

• G01S7/35

  Details of non-pulse systems · CPC title

• A61B5/0205

  Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition · CPC title

• A61B5/02444

  Details of sensor (A61B5/02427 takes precedence) · CPC title