Disclosed is a 5-point-star antenna for radar-based road accident prevention applications, said antenna being able to operate simultaneously or alternately in the x-band and Ku-band ranges and being powered via a single-access jack-type female SMA connector. The invention relates to a new symbolic antenna that has a rectangular substrate and a 5-point-star patch. Said antenna is an electromagnetic transceiver device that can emit in the ultra-wide band (UWB) range and uses a coaxial connector, thus resulting in greater gain, two large bandwidths, a reduced size, good suitability for the x-band and Ku-band frequency bands, and low production costs. The antenna is composed of a single 5-point-star patch connected to the output by means of a coaxial probe. Power is supplied to the antenna directly by a coaxial connector. The power supply point is connected to an SMA connector (figure 7) that is inserted in the ground plane, thereby making it possible to increase gain, directivity and the bandwidth. The device of the invention is particularly suitable for radar applications in the x-band and Ku-band ranges for detecting speeding vehicles.