A wearable multi antenna system on a life jacket for Cospas Sarsat rescue applications

In this paper, a multi antenna system mounted on a life jacket for human rescue Cospas Sarsat applications is described. The latter is intended to provide a earth to satellite SOS communication in case of shipwrecks or similar crashes and it is currently implemented in emergency devices like buoys. In the proposed work, two dipoles have been attached on different floating elements of a life jacket, in order to form a wearable emergency system that could be worn by any survivor. The two antennas are folded meandered dipoles operating at 406 MHz, center frequency of the Cospas sarsat system. A metallic sheet is used to shield the antennas from the human body and it is placed on the opposite side of the floating element with respect to each antenna. Antennas are linearly polarized with good impedance matching also when they are worn by the user, a wide radiation pattern beam and a high gain. Moreover they are orthogonal in order to form a diversity pattern transmitting system. Prototypes have been realized and a measurement campaign has been carried out showing good performance.