In the current scenario, where it is becoming very important for many Health Care Monitoring System to provide non-invasive and non-contact measurements, this paper presents a novel monitoring system for vital signs based on the Frequency Modulated-Ultra Wide Band (FM-UWB) technology. First of all, an analysis of the error introduced by each block of the transceiver device is performed in order to better understand the achievable resolution under no ideal working conditions. Then, a comparison with an IR-UWB monitoring system is performed in terms of sensitivity. As it is expected, the FM-UWB radar, which is a continuous wave radar, can achieve the same resolution also working much lower SNRs than IR-UWB systems. This means that proposed system can work also with lower power levels than an IR-UWB device. Moreover, our simulation confirms that the FM-UWB system can achieve the desired resolution (of the order of mm) for the context of interest (heart-beat, respiration rate monitoring).