THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. 2014 Apr.; 25(4), 418 425. http://dx.doi.org/10.5515/kjkiees.2014.25.4.418 ISSN 1226-3133 (Print) ISSN 2288-226X (Online) Doppler Radar System for Long Range Detection of Respiration and Heart Rate 이지훈 김기범 박성욱 Jee-Hoon Lee Ki-Beom Kim Seong-Ook Park 요약 Ku-Band. ECG(Electrocardiogram). I/Q(In- phase & Quadrature-phase) arctangent demodulation RMSE(Root Mean Square Error) 50 %. CW(Continuous Wave). SNR(Signal-to-Noise Ratio).. leakage cancellation 35 m, ECG. Abstract This paper presents a Ku-Band Doppler Radar System to measure respiration and heart rate. It was measured by using simultaneous radar and ECG(Electrocardiogram). Arctangent demodulation without dc offset compensation can be applied to transmitted I/Q(In-phase & Quadrature-phase) signal in order to improve the RMSE(Root Mean Square Error) about 50 %. The power leaked to receiving antenna from the transmitting antenna is always generated because of continuously opening the transceiver of CW(Continuous Wave) Doppler radar. As the output power increase, leakage power has an effect on the SNR(Signal-to-Noise Ratio) of the system. Therefore, in this paper, leakage cancellation technique that adds the signal having the opposite phase of the leakage power to the leakage power was implemented in order to minimize the decline of receiver sensitivity. By applying the leakage cancellation techniques described above, it is possible to measure the heart rate and respiration of the human at a distance of up to 35 m. the heart rate of the measured data at a distance of 35 m accords with the heart rate extracted from the ECG data. Key words: Heart Rate, Doppler Radar, Leakage Cancellation, Arctangent Demodulation (No. 2013-06-A-02-132-13-010100). (Department of Electrical Engineering, Korea Advanced Institute of Science and Technology) Manuscript received January 27, 2014 ; Revised March 10, 2014 ; Accepted March 20, 2014. (ID No. 20040127-012) Corresponding Author: Seong-Ook Park (e-mail: sopark@ee.kaist.ac.kr) 418 c Copyright The Korean Institute of Electromagnetic Engineering and Science. All Rights Reserved.
. 서론....,.,....,. 2.45 GHz 18 dbm 21 m [1]. SNR(Signal to Noise Ratio). PSD(Power Spectral Density). 25 m, PSD 35 m.,.,.. 2.4 GHz 47 dbm(20 nw) 1 m [2].. 1 mm, 0.1 mm [3],, 10. 46 dbm(25 nw) 2 m PSD.. 도플러레이더시스템 2-1 레이더시스템의구조 RF, I/Q transceiver, I/Q,. 1 RF. 14 GHz. 2.3 GHz PLL,., 14 GHz 16 dbi. 2.3 GHz 11.7 GHz. 14 GHz 1.82 GHz 12.18 GHz 11.7 GHz 480 MHz IF(Intermediate Frequency). IF (quadrature demodulator) 90 I/Q 419
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 4, Apr. 2014. 그림 1. Fig. 1. Block diagram of RF transceiver.. RF IF baseband 60 db 55 db. 1 16, 32 64 PLL(Phase Locked Loop), (BPF), PLL,. 2-2 HRV(Heart Rate Variability) 분석 HRV(Heart Rate Variability) [4]. HRV. SDNN (Standard Deviation of the Normal beat to beat internal), RMSSD (Root Mean Square of Successive heartbeat Interval Differences).., FFT. HRV. 2-3 누설전력감쇄법.,.. SNR MATLAB [5]. 1, 2. 2,,,., 420
(a) (a) Block diagram of RF transceiver 그림 3. IF Fig. 3. IF spectrum with and without leakage cancellation. (b) RF (b) RF stage with leakage cancellation 그림 2. Fig. 2. Doppler radar system with leakage cancellation.. 5 Hz, 5. 3 m, 10 dbm. 3, 480 MHz. 480 MHz 20.88 db. 480 MHz±5 Hz 6.5 db.., 27.4 db.. 호흡및심박수측정결과 180. 3-1 Arctangent Demodulation 을이용한심박수측정의 정확도향상 421
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 4, Apr. 2014. 4 10 dbm 5 m. 4(a) 4(b) I Q, 4(c) 4(a) 4(b) arctangent demodulation, 4(d) ECG. HRV 4(b) (d) (a) (b) 그림 5. 5 m, ECG, Fig. 5. Beat-to-beat intervals of Q-channel, ECG, and arctangent demodulation signals. (c) (d) 그림 4. 5 m. (a) I-, (b) Q-, (c) arctangent demodulation, (d) ECG Fig. 4. Measured heart signal at a distance of 5 meters. (a) I-channel, (b) Q-channel, (c) Arctangent demodulation, (d) ECG signal. 표 1. Q-, arctangent demodulation, ECG HRV Table 1. HRV analysis comparison of Q, arctangent, and ECG. Mean RR (ms) Q ECG RMSE arctan. RMSE Δ 845.28 241.73 40.87 845.37 21.16 19.71 SDNN (ms) RMSSD (ms) Q ECG RMSE arctan. RMSE Δ 43.20 23.58 14.77 72.87 36.76 10.3, HRV 1. Q- ECG RMSE(Root Mean Square Error) 40.87 ms, arctangent demodulation ECG RMSE 21.16 ms 19.71 ms. SDNN RMSSD arctangent demodulation ECG. 5 Q- ( 4(b)) arctangent demodulation ( 4(c)), ECG( 4(d)). 1 5 Q- ECG,. 3-2 저출력송신신호를이용한근거리호흡및심박검출. 2 m 46 dbm(25 nw), 6 422
(a) (a) Respiration signal by radar 그림 7. 35 m Fig. 7. Experiment set-up for long range detection. (b) (b) Heart signal by radar and ECG detector (a) (a) Respiration signal by radar 그림 6. 2 m Fig. 6. The measurement results when transmission power is 46 dbm at a distance of 2 meters.. 3-3 고출력송신신호를이용한원거리호흡및심 박검출., leakage cancellation. (b) (b) Heart signal by radar and ECG detector 그림 8. 35 m Fig. 8. The measurement results when transmission power is 23 dbm at a distance of 35 meters. 423
THE JOURNAL OF KOREAN INSTITUTE OF ELECTROMAGNETIC ENGINEERING AND SCIENCE. vol. 25, no. 4, Apr. 2014. 23 dbm(200 mw) 35 m. 7 35 m. 8(a) 35 m 0.31 Hz, 18.6. 8(b) ECG 1.094 Hz, 65.64. ECG,.. 결론,., 0 dbm. 2 m 25 nw.. leakage cancellation., 35 m., arctangent demodulation HRV. References [1] M. Baboli, A. Singh, N. Hafner, and V. Lubecke, "Parametric study of antenna for long range Doppler radar heart rate detection", International Conference of the IEEE EMBS, USA, 2012. [2] Shuhei Yamada, Mingqui Chen, and Victor Lubecke, "Sub-uW signal power Doppler radar heart rate detection", APMC, 2006. [3] M. Singh, G. Ramachandran, "Reconstruction of sequential cardiac in-plane displacement patterns on the chest wall by laser speckle interferometry", IEEE Trans. Bioded. Eng., vol. 38, pp. 483-489, 1999. [4] D. H. Kim, "Heart rate variability", Current Practice in Cardiology, vol. 5, no. 10, 2011. [5] B. J. Jang, S. H. Wi, J. G. Yook, M. Q. Lee, and K. J. Lee, "Wireless bio-radar sensor for heartbeat and respriation detection", Progress In Electromagnetics Research C, vol. 5, 2008. [6] Manh-Tuan Dao, Dong-Hun Shin, Yun-Taek Im, and Seong-Ook Park, "A two sweeping VCO source for heterodyne FMCW radar," IEEE Trans. on Instrumentation and Measurement., vol. 62, no. 1, Jan. 2013. 2007 2 : ( ) 2009 2 : ( ) 2009 3 : [ 주관심분야 ], RF 2011 7 : ( ) 2011 9 : [ 주관심분야 ] RF Baseband system 424
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