Ultra wideband monitoring systems and antennas

Apparatus for monitoring vital signs of one or more living subjects, the apparatus comprising:

• a monitoring station;
• at least one sensor in communication with the monitoring station, the sensor comprising:
• an antenna system;
• an ultra wideband radar system coupled to the antenna system;
• a signal processor connected to receive a signal from the ultra wideband radar system and configured to extract from the signal information about one or more vital signs of a living subject in a sensing volume corresponding to the antenna system;
• and
• a communication system configured to transmit the information to the monitoring station;
• wherein the antenna system comprises one or more groups of antennas and each group of antennas comprises:
• a transmit antenna connected to transmit ultra wideband pulses generated by the ultra wideband radar system;
• and a plurality of receive antennas spaced apart from the transmit antenna and connected to receive ultra wideband pulses reflected by the living subject;
• and wherein, for each group of antennas, the plurality of receive antennas have higher gains than the transmit antenna,
• wherein the antenna system comprises a generally planar substrate and at least one antenna that comprises a first element on a first side of the substrate and a second element on a second side of the substrate opposed to the first side, wherein each of the first and second elements are symmetrical about a center line and have curved edges at locations near their feedpoint, and
• wherein each of the elements comprises a plurality of stubs and wherein at least one of:
• the stubs are pointed;
• the stubs are of different lengths;
• and the stubs include a central stub having edges that follow intersecting straight lines.