%0 Electronic Article %A S. Okumura %+ Graduate School of Informatics, Kyoto University, Yoshida-Honmachi, Sakyoku, Kyoto, Japan %A T. Sakamoto %+ Graduate School of Informatics, Kyoto University, Yoshida-Honmachi, Sakyoku, Kyoto, Japan %A T. Sato %+ Graduate School of Informatics, Kyoto University, Yoshida-Honmachi, Sakyoku, Kyoto, Japan %A M. Yoshioka %+ Advanced Research Division, Panasonic Corporation, Hikaridai 3-4, Seika-cho, Souraku-gun, Kyoto, Japan %A K. Inoue %+ Advanced Research Division, Panasonic Corporation, Hikaridai 3-4, Seika-cho, Souraku-gun, Kyoto, Japan %A T. Fukuda %+ Advanced Research Division, Panasonic Corporation, Hikaridai 3-4, Seika-cho, Souraku-gun, Kyoto, Japan %A H. Sakai %+ Advanced Research Division, Panasonic Corporation, Hikaridai 3-4, Seika-cho, Souraku-gun, Kyoto, Japan %K vital signs %K phase rotation angles %K Doppler radar %K clutter rejection techniques %K time-varying echo phase %K body surface %K numerical analysis %K human body %K small displacements measurement %K upper torso %X To measure vital signs using Doppler radar, a common approach involves the use of time-varying echo phase. To acquire these measurements, clutter rejection is necessary because clutter power is often larger than echo power. To reject static clutter, several techniques have been proposed that assume relatively large phase rotation angles because many studies assume the measurement of the upper torso, where displacement is mainly caused by respiration. However, signals from other parts of the human body are known to have smaller displacements that exhibit small phase rotation angles, which make clutter rejection more difficult. Three clutter rejection techniques for measuring small displacements are compared and their performances are investigated. Using numerical analysis, one method is demonstrated to be the most effective, even for small displacements in noisy data. The best method successfully estimates the centre with an error of −13.4 and −24.0 dB, with a signal-to-noise ratio of 10 and 40 dB and the range of phase rotation angles of 90° and 15°. %@ 0013-5194 %T Comparison of clutter rejection techniques for measurement of small displacements of body surface using radar %B Electronics Letters %D September 2016 %V 52 %N 19 %P 1635-1637 %I Institution of Engineering and Technology %U https://digital-library.theiet.org/;jsessionid=tk91hicf98lr.x-iet-live-01content/journals/10.1049/el.2016.1461 %G EN