Dipole antenna for microwave ablation

An antenna system comprising:

• a coaxial cable comprising
• a center conductor extending a length of the coaxial cable;
• a dielectric material surrounding the center conductor along the length of the coaxial cable;
• and
• a conductive shield surrounding the dielectric material along the length of the coaxial cable;
• and
• an antenna comprising
• a first dipole arm connected to the center conductor and formed of a first conducting material, wherein the first dipole arm extends in an axial direction from the center conductor;
• and
• a second dipole arm connected to the conductive shield that is distinct from the center conductor and formed of a second conducting material, wherein the second dipole arm extends in the axial direction from the conductive shield and is wound around the first dipole arm to form a number of loops, wherein the second dipole arm does not contact the first dipole arm,
• wherein an axial length of the second dipole arm in the axial direction is less than 90% of an axial length of the first dipole arm in the axial direction, wherein the axial length of the first dipole arm is approximately 0.25λ, where λ is a wavelength at an operating frequency of a signal carried by the first conductor and the second conductor in a medium in which the antenna is selected to operate, wherein the axial length of the second dipole arm is between 0.1λ and 0.2λ, inclusive.

A microwave ablation system comprising:

• an antenna system comprising
• a coaxial cable comprising
• a center conductor extending a length of the coaxial cable;
• a dielectric material surrounding the center conductor along the length of the coaxial cable;
• and
• a conductive shield surrounding the dielectric material along the length of the coaxial cable;
• an antenna comprising
• a first dipole arm connected to the center conductor and formed of a first conducting material, wherein the first dipole arm extends in an axial direction from the center conductor;
• and
• a second dipole arm connected to the conductive shield that is distinct from the center conductor and formed of a second conducting material, wherein the second dipole arm extends in the axial direction from the conductive shield and is wound around the first dipole arm to form a number of loops, wherein the second dipole arm does not contact the first dipole arm,
• wherein an axial length of the second dipole arm in the axial direction is less than 90% of an axial length of the first dipole arm in the axial direction;
• a signal generator configured to generate a signal at a selected operating frequency;
• and
• a connector configured to connect a second end of the coaxial cable opposite the antenna to the signal generator to receive the generated signal.