A system is presented for non-invasive monitoring one or more blood conditions of a media in a region of interest. The system comprises: a sensor device comprising at least one antenna sensor configured to be placed in the vicinity of the media and configured and operable to generate antenna beams of different frequencies in a frequency range of about 100 MHz to 90 GHz, receive radiation responses from the medium, and generate corresponding sensing data; and a control unit configured to receive and process said sensing data to determine a dielectric spectrum of the media indicative of dielectric response of cytoplasm containing cells (red blood cells) in the media and determine one or more blood conditions.