A microwave ablation probe for providing microwave energy to tissue is disclosed. The probe includes a feedline having an inner conductor and an insulating spacer and an outer conductor. The probe also includes a radiation portion having an extruded portion of the inner conductor that is centrally disposed therein. The radiation portion also includes one or more conductive disks disposed ON the extruded portion of the inner conductor that defines one or more spaces and a dielectric material disposed within the spaces.