Tools for Attacking Tumors: Performance Comparison of Triaxial, Choke Dipole, and Balun-Free Base-Fed Monopole Antennas for Microwave Ablation

Microwave ablation (MWA) is a promising therapeutic technique that uses minimally invasive interstitial antennas for heating tumors to cytotoxic temperatures [1], [2]. Over the years, numerous MWA antennas have been reported in the literature (e.g., [3]-[15]). MWA antenna designs typically use coaxial cable feed lines to deliver the microwave energy to the active part of the antenna. Due to the unbalanced nature of coaxial cables, current can flow on the outer surface of the outer conductor. If not appropriately suppressed, this current can cause unwanted heating of healthy tissue along the antenna?s insertion path. Moreover, in such situations, the input impedance of the antenna becomes dependent on the insertion depth.