RF sensors has acquired a great importance in the day to day life of human beings irrespective of its social or financial strata. The features like non-invasiveness, low cost and high accuracy in detection of tiny human vital signs makes RF sensor attractive for the various day to day activities. Further, such sensors finds its utility in the field of law enforcement, military and battle grounds, sports and healthcare sectors to ascertain the existence of human life. Considering these facts, the present section of the monograph describes the motivation and necessity behind the design and development of a noninvasive RF sensor.