An electrosurgical device for delivering energy to tissue, comprises an antenna assembly (12) defining a longitudinal axis. The antenna assembly includes a first dielectric segment (284) and a second dielectric segment (274) configured to be coupled to the first dielectric segment about the longitudinal axis of the antenna assembly. The first and second dielectric segments cooperatively define a longitudinal channel extending along the longitudinal axis. A feedline (226) including an inner conductor (2, 220) is disposed within the channel of the first (284) and second (287) dielectric segments.
