{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,11]],"date-time":"2025-11-11T15:41:13Z","timestamp":1762875673887,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2015,3,16]],"date-time":"2015-03-16T00:00:00Z","timestamp":1426464000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Human respiratory patterns at chest and abdomen are associated with both physical and emotional states. Accurate measurement of the respiratory patterns provides an approach to assess and analyze the physical and emotional states of the subject persons. Not many research efforts have been made to wirelessly assess different respiration patterns, largely due to the inaccuracy of the conventional continuous-wave radar sensor to track the original signal pattern of slow respiratory movements. This paper presents the accurate assessment of different respiratory patterns based on noncontact Doppler radar sensing. This paper evaluates the feasibility of accurately monitoring different human respiration patterns via noncontact radar sensing. A 2.4 GHz DC coupled multi-radar system was used for accurate measurement of the complete respiration patterns without any signal distortion. Experiments were carried out in the lab environment to measure the different respiration patterns when the subject person performed natural breathing, chest breathing and diaphragmatic breathing. The experimental results showed that accurate assessment of different respiration patterns is feasible using the proposed noncontact radar sensing technique.<\/jats:p>","DOI":"10.3390\/s150306383","type":"journal-article","created":{"date-parts":[[2015,3,16]],"date-time":"2015-03-16T11:17:39Z","timestamp":1426504659000},"page":"6383-6398","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":68,"title":["Assessment of Human Respiration Patterns via Noncontact Sensing Using Doppler Multi-Radar System"],"prefix":"10.3390","volume":"15","author":[{"given":"Changzhan","family":"Gu","sequence":"first","affiliation":[{"name":"Marvell Technology Group Ltd., 5488 Marvell Lane, Santa Clara, CA 95054, USA"},{"name":"Department of Electrical and Computer Engineering, Texas Tech University, Lubbock,  TX 79409, USA"}]},{"given":"Changzhi","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Texas Tech University, Lubbock,  TX 79409, USA"}]}],"member":"1968","published-online":{"date-parts":[[2015,3,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1016\/0167-8760(91)90006-J","article-title":"Specific respiratory patterns distinguish among human basic emotions","volume":"11","author":"Bloch","year":"1991","journal-title":"Int. J. Psychophysiol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1111\/j.1748-1716.2006.01529.x","article-title":"Breathing pattern and kinematics in normal subjects during speech, singing and loud whispering","volume":"186","author":"Binazzi","year":"2006","journal-title":"Acta Physiol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1011","DOI":"10.1113\/expphysiol.2008.042424","article-title":"Breathing rhythms and emotions","volume":"93","author":"Homma","year":"2008","journal-title":"Exp. Physiol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1016\/S0892-1997(01)00009-1","article-title":"Patterns of Breath Support in Projection of the Singing Voice","volume":"15","author":"Thorpe","year":"2001","journal-title":"J. Voice"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"420","DOI":"10.1002\/ajim.10061","article-title":"A hyperventilation theory of job stress and musculoskeletal disorders","volume":"41","author":"Schleifer","year":"2002","journal-title":"Am. J. Ind. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1724","DOI":"10.1109\/TMTT.2003.812575","article-title":"A displacement measurement technique using millimeter-wave interferometry","volume":"51","author":"Kim","year":"2003","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1109\/TITB.2009.2034011","article-title":"Nonconstrained Sleep Monitoring System and Algorithms Using Air-Mattress with Balancing Tube Method","volume":"14","author":"Shin","year":"2010","journal-title":"IEEE Trans. Inf. Technol. Biomed."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"890","DOI":"10.1109\/TITB.2009.2031239","article-title":"Automatic Detection of Respiration Rate from Ambulatory Single-Lead ECG","volume":"13","author":"Boyle","year":"2009","journal-title":"IEEE Trans. Inf. Technol. Biomed."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"10837","DOI":"10.3390\/s101210837","article-title":"Detecting Vital Signs with Wearable Wireless Sensors","volume":"10","author":"Yilmaz","year":"2010","journal-title":"Sensors"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4527","DOI":"10.3390\/s130404527","article-title":"Localization and Mapping Using Only a Rotating FMCW Radar Sensor","volume":"13","author":"Vivet","year":"2013","journal-title":"Sensors"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"8992","DOI":"10.3390\/s110908992","article-title":"Integrating Millimeter Wave Radar with a Monocular Vision Sensor for On-Road Obstacle Detection Applications","volume":"11","author":"Wang","year":"2011","journal-title":"Sensors"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1002\/bem.2250130610","article-title":"Microwave sensing of physiological movement and volume change: A review","volume":"13","author":"Lin","year":"1992","journal-title":"Bioelectromagnetics"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1109\/TBME.1986.325760","article-title":"An X-band microwave life-detection system","volume":"7","author":"Chen","year":"1986","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"96","DOI":"10.1007\/s10527-013-9343-8","article-title":"Estimation of information value of diagnostic data obtained by bioradiolocation pneumography in noncontact screening of sleep apnea syndrome","volume":"47","author":"Alekhin","year":"2013","journal-title":"Biomed. Eng."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1111\/j.1365-2869.2012.01056.x","article-title":"Assessment of sleep disordered breathing using a noncontact biomotion sensor","volume":"22","author":"Zaffaroni","year":"2013","journal-title":"J. Sleep Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"3117","DOI":"10.1109\/TBME.2012.2206591","article-title":"Accurate Respiration Measurement Using DC-Coupled Continuous-Wave Radar Sensor for Motion-Adaptive Cancer Radiotherapy","volume":"59","author":"Gu","year":"2012","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1073","DOI":"10.1109\/TMTT.2007.895653","article-title":"Arctangent demodulation with DC offset compensation in quadrature Doppler radar receiver systems","volume":"55","author":"Park","year":"2007","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"344","DOI":"10.1049\/el.2012.0071","article-title":"DC coupled CW radar sensor using fine-tuning adaptive feedback loop","volume":"48","author":"Gu","year":"2012","journal-title":"Electron. Lett."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Gu, C., Salmani, Z., Zhang, H., and Li, C. (2012, January 15\u201318). Antenna Array Technology for Radar Respiration Measurement in Motion-Adaptive Lung Cancer Radiotherapy. Proceedings of the 2012 IEEE Topical Conference on Biomedical Wireless Technologies, Networks, and Sensing Systems (BioWireleSS), Santa Clara, CA, USA.","DOI":"10.1109\/BioWireless.2012.6172731"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2542","DOI":"10.1109\/TMTT.2009.2029716","article-title":"Assessment of Heart Rate Variability and Respiratory Sinus Arrhythmia via Doppler Radar","volume":"57","author":"Massagram","year":"2009","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Boric-Lubecke, O., Massagram, W., Lubecke, V.M., Host-Madsen, A., and Jokanovic, B. (2008, January 27\u201331). Heart rate variability assessment using Doppler radar with linear demodulation. Proceedings of the 38th European Microwave Conference, Amsterdam, The Netherlands.","DOI":"10.1109\/EUMC.2008.4751478"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"600","DOI":"10.1016\/S1579-2129(10)70128-2","article-title":"Effectiveness of Therapeutic Education and Respiratory Rehabilitation Programs for the Patient with Asthma","volume":"46","author":"Cuerda","year":"2010","journal-title":"Arch. Bronconeumol."},{"key":"ref_23","unstructured":"FCC Rules for Unlicensed Wireless Equipment Operating in the ISM Bands. Available online: http:\/\/www.afar.net\/tutorials\/fcc-rules."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1410","DOI":"10.1109\/TMTT.2010.2042856","article-title":"High-Sensitivity Software-Configurable 5.8-GHz Radar Sensor Receiver Chip in 0.13-\u00b5m CMOS for Noncontact Vital Sign Detection","volume":"58","author":"Li","year":"2010","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1177\/1479972311424296","article-title":"Efficacy of diaphragmatic breathing in patients with chronic obstructive pulmonary disease","volume":"8","author":"Fernandes","year":"2011","journal-title":"Chron. Respir. Dis."},{"key":"ref_26","unstructured":"Diaphragmatic Breathing. Available online: http:\/\/en.wikipedia.org\/wiki\/Diaphragmatic_breathing."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"838","DOI":"10.1109\/TMTT.2004.823552","article-title":"Range correlation and I\/Q performance benefits in single-chip silicon Doppler radars for noncontact cardiopulmonary monitoring","volume":"52","author":"Droitcour","year":"2004","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"15371","DOI":"10.3390\/s140815371","article-title":"An Ultrasonic Contactless Sensor for Breathing Monitoring","volume":"14","author":"Arlotto","year":"2014","journal-title":"Sensors"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/3\/6383\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:43:33Z","timestamp":1760215413000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/3\/6383"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,3,16]]},"references-count":28,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2015,3]]}},"alternative-id":["s150306383"],"URL":"https:\/\/doi.org\/10.3390\/s150306383","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2015,3,16]]}}}