A high-band radiator of an ultra-wideband dual-band basestation antenna is disclosed. The high-band radiator comprises at least one dipole, a feed stalk, and a tubular body made of conductive material and having an annular flange. Each dipole comprises two dipole arms made of conductive material. The feed stalk feeds the dipole and comprises a non-conductive dielectric substrate body and conductors formed on the substrate body to function as a balun transformer. The feed stalk is connected with the dipole at one end and has at least one feed connector at the other, with the conductors coupled there-between. The tubular body is adapted for electrical connection through the annular flange to the ground plane at the open end; the body is short-circuited at the other end to define an internal cavity of the tubular body. At least a portion of the feed stalk is disposed within the tubular body.