Analysis of return loss with an uncooled coaxial monopole antenna during microwave ablation

Abstract

Microwave tumour ablation is a percutaneous cancer treatment that irreversibly destroys tumour cells with heat, where high temperatures over 100℃ are reached. The process involves the interaction of microwave electric fields with biological tissue. This interaction is dependent on the temperature-dependent dielectric permittivity and effective conductivity. A dual-mode microwave ablation system was developed to measure dielectric properties utilising an uncooled insulated monopole. As a preliminary study, the return loss during ablation was investigated at 2.45 GHz. This was measured using a power meter during powered conditions and a Vector Network Analyser (VNA) with controlled switching. Three different power conditions were employed: 10 W, 30 W and 50 W. Although deviations were obtained during specific instances, a relative agreement was obtained between the return losses measured with the power meter and VNA. Ultimately, this paper briefly discusses the possible causes that led to the measurement deviations experienced with the presented ablation technique.