title: A versatile microwave plethysmograph for the monitoring of physiological parameters.
abstract: A simple microwave technique for in vivo monitoring of human pulmonary and cardiac activity is here presented. The technique is based on detecting the changes in the modulation envelope of amplitude modulated waves passing through the human body. A simplified human chest model was developed, proving an unambiguous correlation between heart blood filling and microwave transmission through the chest. A prototype system for transmittance measurement was realized at the 868.5-MHz operating frequency, demonstrating the feasibility of a small, lowcost microwave plethysmograph. In vivo measurements showed a good agreement with numerical simulations.
authors.affiliation: Department of Electronics and Telecommunications, University of Florence, Italy.
authors.forename: Guido Biffi
authors.initials: GB
authors.lastname: Gentili
authors.forename: Vasco
authors.initials: V
authors.lastname: Tesi
authors.forename: Mariano
authors.initials: M
authors.lastname: Linari
authors.forename: Massimo
authors.initials: M
authors.lastname: Marsili
mesh_terms: D003198:Computer Simulation; D003326:Coronary Circulation / Q000502:physiology; D004867:Equipment Design; D006321:Heart / Q000502:physiology; D006801:Humans; D008872:Microwaves; D008954:Models, Biological; D010991:Plethysmography / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D015656:Respiratory Mechanics / Q000502:physiology; D012680:Sensitivity and Specificity; D013909:Thorax / Q000098:blood supply* / Q000502:physiology*