Patent ID: 8512329

Claim:
An electrosurgical system for treating tissue, the system comprising: an electrosurgical generator configured to generate microwave energy; and an antenna assembly configured to radiate the microwave energy, the antenna assembly comprising: a first elongated conductor associated with a first radiating portion at least partially along the length thereof; a second elongated conductor disposed within the first elongated conductor and associated with a second radiating portion at least partially along the length thereof; and a dielectric body portion disposed along the length of at least one of the first elongated conductor and the second elongated conductor, the dielectric body portion including at least two radial partitions of dielectric material having different dielectric constants, wherein the electrosurgical generator includes an S-parameter sensor configured to determine at least one S-parameter of the antenna assembly and wherein the first dielectric body portion causes the first radiating portion to have a radiation pattern including at least one elongated radiation lobe, wherein the electrosurgical generator associates the determined at least one S-parameter with an angular direction of the at least one elongated radiation lobe.