The invention provides an ultra-wideband antenna. The ultra-wideband antenna comprises a dielectric substrate, wherein a radiation unit, a feeding structure and a ground plane are printed on the dielectric substrate; the radiation unit is a forked chip; the feeding structure is a coplanar waveguide feeding structure; and the ground plane is a coplanar waveguide ground plane. The ultra-wideband antenna has a coplanar waveguide structure, so that a single planar printed antenna structure can be realized; the ultra-wideband antenna can be easily integrated with a microwave integrated circuit; the coplanar waveguide ground plane can serve as the ground plane of the whole antenna, and particularly for the coplanar waveguide structure with a wideband slot structure, wideband work can be realized, and the electromagnetic interference of outside on the antenna can be effectively avoided; and wideband impedance bandwidth can be easily realized, and the efficiency of the antenna is improved, so that higher antenna gain can be achieved.