Microwave ablation antenna system

A transmitter comprising:

• an antenna system comprising
• a coaxial cable comprising
• a center conductor extending a length of the coaxial cable made of a first conductive material;
• a first dielectric material surrounding the center conductor along the length of the coaxial cable;
• and
• a conductor surrounding the first dielectric material along the length of the coaxial cable made of a second conductive material;
• a base fed monopole type antenna comprising a conductor having an electrical length of half a wavelength at a selected operating frequency for the antenna system,
• wherein the conductor is configured to radiate an electromagnetic wave into surrounding tissue when the antenna system is used;
• and
• an impedance matching structure comprising
• a second center conductor located between an end of the center conductor of the coaxial cable and a feed connector of the antenna as a continuous extension of the first conductive material of the center conductor of the coaxial cable;
• a second conductive shield that is a continuous extension of the second conductive material of the conductive shield of the coaxial cable;
• a capacitive section located adjacent a feed end of the feed connector of the antenna, the capacitive section comprising
• a second dielectric material surrounding a portion of the second center conductor that extends the length of the capacitive section;
• and
• a third conductive material that surrounds the second dielectric material along the length of the capacitive section,
• wherein a portion of the second conductive shield that extends the length of the capacitive section surrounds the third conductive material;
• and
• an inductive section located adjacent the capacitive section on a side of the capacitive section opposite the feed end of the feed connector of the antenna, the inductive section comprising
• a third dielectric material surrounding a portion of the second center conductor that extends the length of the inductive section,
• wherein a portion of the second conductive shield that extends the length of the inductive section surrounds the third dielectric material,
• wherein the impedance matching structure is configured to match an impedance of the coaxial cable to an impedance of the antenna;
• a signal generator configured to generate a signal at the selected operating frequency;
• and
• a connector configured to connect a second end of the coaxial cable opposite the end of the center conductor to the signal generator to receive the generated signal.