This paper reviews recent advances in technologies using Doppler radar to detect heartbeat and respiration of a human subject. With contributions from many researchers in this field, new detection methods and system architectures have been proposed to improve the detection accuracy and robustness. The advantage of noncontact/covert detection has drawn interests on various applications. While many of the reported systems are bench-top prototypes for concept demonstration, several portable systems and integrated radar chips have been demonstrated. This paper reviews different architectures and discusses their potentials for integrated circuit implementation. Integrating the radar sensor on a chip allows the function of noncontact vital sign and vibration detection to be embedded in portable electronic equipment, like many other radio frequency (RF) devices. A radar sensor network is then feasible for pervasive monitoring in healthcare applications.