A multifrequency interferometric CW radar for vital signs detection

The use of radar techniques to detect minute body movements which are associated with respiration and cardiac activity (vital signs) is known at least since 1975 when J.C. Linn and J. Salinger proposed a non-contact microwave respiration monitor. This paper sets up to discuss further development of CW radar based vital signs detection systems. The purpose here is to enhance target detection probability in a highly cluttered environment and to add range and angle-of-arrival estimation without dramatically enhancing RF spectrum requirements by transition to a multicarrier interrogating signal.