A collar with an ultra-wideband radar is described. A housing contains sensor electronics and the transmit and receive antennas are located separate from the housing around the circumference of the collar. A first example of the collar includes a first transmit antenna and a first receive antenna. A second example of the collar adds a second transmit antenna and a second receive antenna. The antennas may be positioned to obtain position and movement information from various internal structures including a carotid artery and a jugular vein for monitoring heart rate and muscles surrounding an esophagus and trachea for monitoring of respiration.
