An electrosurgical instrument comprising: a coaxial feed cable for conveying microwave energy and radiofrequency energy, the coaxial feed cable having an inner conductor, an outer conductor, and a dielectric material separating the inner conductor and the outer conductor; and a radiating tip disposed at a distal end of the coaxial cable to receive the microwave energy and the radiofrequency energy, the radiating tip comprising: a longitudinally extending dielectric body; a distal electrode and a proximal electrode disposed on a surface of the dielectric body, wherein the distal electrode and the proximal electrode are physically separated from each other in the longitudinal direction by an intermediate portion of the longitudinally extending dielectric body; and a tuning element mounted in the intermediate portion of the longitudinally extending dielectric body and electrically connected to the inner conductor, the tuning element comprising an electrically conductive body mounted within the intermediate portion of the dielectric body, wherein the distal electrode is electrically connected to the inner conductor, wherein the proximal electrode is electrically connected to the outer conductor, wherein the distal electrode and proximal electrode are configured as an active electrode and a return electrode for delivering the radiofrequency energy, and wherein the radiating tip is operable as an antenna for emitting the microwave energy. a coaxial feed cable for conveying microwave energy and radiofrequency energy, the coaxial feed cable having an inner conductor, an outer conductor, and a dielectric material separating the inner conductor and the outer conductor; and a radiating tip disposed at a distal end of the coaxial cable to receive the microwave energy and the radiofrequency energy, the radiating tip comprising: a longitudinally extending dielectric body; a distal electrode and a proximal electrode disposed on a surface of the dielectric body, wherein the distal electrode and the proximal electrode are physically separated from each other in the longitudinal direction by an intermediate portion of the longitudinally extending dielectric body; and a tuning element mounted in the intermediate portion of the longitudinally extending dielectric body and electrically connected to the inner conductor, the tuning element comprising an electrically conductive body mounted within the intermediate portion of the dielectric body, a longitudinally extending dielectric body; a distal electrode and a proximal electrode disposed on a surface of the dielectric body, wherein the distal electrode and the proximal electrode are physically separated from each other in the longitudinal direction by an intermediate portion of the longitudinally extending dielectric body; and a tuning element mounted in the intermediate portion of the longitudinally extending dielectric body and electrically connected to the inner conductor, the tuning element comprising an electrically conductive body mounted within the intermediate portion of the dielectric body, wherein the distal electrode is electrically connected to the inner conductor, wherein the proximal electrode is electrically connected to the outer conductor, wherein the distal electrode and proximal electrode are configured as an active electrode and a return electrode for delivering the radiofrequency energy, and wherein the radiating tip is operable as an antenna for emitting the microwave energy.