Patent ID: 9050115
Filing Date: 2015-06-09
Classification: A61B

Abstract:
1. A surgical instrument having: a waveguide for carrying microwave energy having a frequency between 5 GHz and 100 GHz; and a cutting element connected to the waveguide to receive the microwave energy therefrom, the cutting element comprising a piece of dielectric material configured to load the waveguide, wherein the piece of dielectric material includes: a sharpened edge forming a blade for cutting biological tissue; a radiating antenna for emitting the microwave energy as a microwave radiation field from the sharpened edge into the biological tissue; and an impedance transformer arranged to provide substantially maximum field coupling from the waveguide to the cutting element, the impedance transformer being integrally formed with the cutting element and arranged to match a first impedance, which is an impedance of the waveguide before it is loaded with the piece of dielectric material, with a second impedance, which is a predetermined impedance of the biological tissue, wherein the piece of dielectric material comprises a piece of ceramic having a metallised surface except for a first unmetallised region at a proximal coupling portion and a second unmetallised region at the sharpened edge, wherein the radiating antenna is formed by the second unmetallised region, and wherein the impedance transformer is located between the waveguide and the sharpened edge.