title: Physical working principles of medical radar.
abstract: There has been research interest in using radar for contactless measurements of the human heartbeat for several years. While many systems have been demonstrated, not much attention have been given to the actual physical causes of why this work. The consensus seems to be that the radar senses small body movements correlated with heartbeats, but whether only the movements of the body surface or reflections from internal organs are also monitored have not been answered definitely. There has recently been proposed another theory that blood perfusion in the skin could be the main reason radars are able to detect heartbeats. In this paper, an experimental approach is given to determine the physical causes. The measurement results show that it is the body surface reflections that dominate radar measurements of human heartbeats.
authors.affiliation: Norwegian Defence Research Establishment, 2027 Kjeller, Norway. oyvind.aardal@ffi.no
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Aardal
authors.forename: Yoann
authors.initials: Y
authors.lastname: Paichard
authors.forename: Sverre
authors.initials: S
authors.lastname: Brovoll
authors.forename: Tor
authors.initials: T
authors.lastname: Berger
authors.forename: Tor Sverre
authors.initials: TS
authors.lastname: Lande
authors.forename: Svein-Erik
authors.initials: SE
authors.lastname: Hamran
mesh_terms: D000328:Adult; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D008991:Monitoring, Physiologic / Q000379:methods; D011825:Radar; D011846:Radio Waves; D012039:Regional Blood Flow / Q000502:physiology; D012867:Skin / Q000098:blood supply; D013909:Thorax / Q000502:physiology