A new system-on-a-chip radar sensor for next generation wearable wireless interface applied to the human health-care and safeguard is presented. The system overview is provided and a summary of the feasibility study of the radar sensor is presented. In detail, the overall system consists of a radar sensor for detecting the heart and breath rates and a low-power IEEE 802.15.4 ZigBee radio interface, which provides a wireless data link with remote data acquisition and control units. Particularly, the pulse radar exploits 3.1-10.6 GHz ultra wide band signals, which allow a significant reduction of the transceiver complexity and, then, of its power consuption. The operating principle is highlighted and the results of the system analysis are summarized. Such a novel system-on-a-chip wireless wearable interface enables low-cost silicon technologies for contactless measuring of the primary vital signs and extends the capability in terms of applications for the emerging wireless body area networks.