Low-band radiators of an ultra-wideband dual-band dual-polarization cellular basestation antenna are provided. The dual bands include low and high bands. The low-band radiator includes a dipole with two dipole arms adapted for the low band and for connection to an antenna feed. At least one dipole arm of the dipole includes at least two dipole segments and at least one radio frequency choke. The choke is disposed between the dipole segments. Each choke provides an open circuit or a high impedance separating adjacent dipole segments to minimize induced high band currents in the low-band radiator and consequent disturbance to the high band pattern. The choke is resonant at or near the frequencies of the high band.