An ablation probe, comprising: a coaxial feedline having an inner conductor, an outer conductor disposed coaxially about the inner conductor, and a dielectric disposed therebetween, wherein the inner conductor and dielectric extend beyond a distal end of the outer conductor; a radiating section having a proximal end operably coupled to a distal end of the inner conductor; a distal tip coupled to a distal end of the radiating section, wherein the distal tip includes a generally cylindrical proximal tip extension; a conductive tube; at least one fluid conduit (140, 152, 153) defined longitudinally within the conductive tube; and a catheter coaxially disposed around the conductive tube, wherein a distal end of the catheter is joined to a proximal end of the distal tip to define a coolant chamber therein; characterized in that: at least one o-ring is disposed about the proximal tip extension and that the catheter is disposed about the o-ring; a balun short (110, 113) disposed in electrical communication around the outer conductor, wherein the balun short (110, 113) includes at least two first notches defined therein adapted to receive a rib member and includes at least two second notches defined radially therebetween, and wherein the conductive tube is disposed coaxially around the balun short (110, 113); and the ablation probe further comprises at least two rib members disposed longitudinally along the outer conductor and positioned at least partially within one of the at least two first notches to define at least two fluid conduits (152, 153) within the conductive tube. a coaxial feedline having an inner conductor, an outer conductor disposed coaxially about the inner conductor, and a dielectric disposed therebetween, wherein the inner conductor and dielectric extend beyond a distal end of the outer conductor; a radiating section having a proximal end operably coupled to a distal end of the inner conductor; a distal tip coupled to a distal end of the radiating section, a conductive tube; at least one fluid conduit (140, 152, 153) defined longitudinally within the conductive tube; and a catheter coaxially disposed around the conductive tube, wherein a distal end of the catheter is joined to a proximal end of the distal tip to define a coolant chamber therein; characterized in that: at least one o-ring is disposed about the proximal tip extension and that the catheter is disposed about the o-ring; a balun short (110, 113) disposed in electrical communication around the outer conductor, wherein the balun short (110, 113) includes at least two first notches defined therein adapted to receive a rib member and includes at least two second notches defined radially therebetween, and wherein the conductive tube is disposed coaxially around the balun short (110, 113); and the ablation probe further comprises at least two rib members disposed longitudinally along the outer conductor and positioned at least partially within one of the at least two first notches to define at least two fluid conduits (152, 153) within the conductive tube. characterized in that: at least one o-ring is disposed about the proximal tip extension and that the catheter is disposed about the o-ring; a balun short (110, 113) disposed in electrical communication around the outer conductor, wherein the balun short (110, 113) includes at least two first notches defined therein adapted to receive a rib member and includes at least two second notches defined radially therebetween, and wherein the conductive tube is disposed coaxially around the balun short (110, 113); and the ablation probe further comprises at least two rib members disposed longitudinally along the outer conductor and positioned at least partially within one of the at least two first notches to define at least two fluid conduits (152, 153) within the conductive tube. at least one o-ring is disposed about the proximal tip extension and that the catheter is disposed about the o-ring; a balun short (110, 113) disposed in electrical communication around the outer conductor, wherein the balun short (110, 113) includes at least two first notches defined therein adapted to receive a rib member and includes at least two second notches defined radially therebetween, and wherein the conductive tube is disposed coaxially around the balun short (110, 113); and the ablation probe further comprises at least two rib members disposed longitudinally along the outer conductor and positioned at least partially within one of the at least two first notches to define at least two fluid conduits (152, 153) within the conductive tube.