A Twin Spiral Planar Antenna for UWB Medical Radars
A planar-spiral antenna to be used in an UltraWideBand (UWB) radar system for heart activity monitoring is presented. The antenna, named "Twin," is constituted by two spiral dipoles in a compact structure. The reflection coefficient at the feed point of the dipoles is lower than 3-8 dB over the 3 - 12 GHz band, while the two-dipoles coupling are about 20 dB. The radiated beam is perpendicular to the plane of the spiral, so the antenna is wearable and it may be an optimal radiator for medical UWB radar for heart rate detection. The designed antenna has been also used to check some hypotheses about the UWB radar heart activity detection mechanism.