Dielectric Sensitivity of Different Antennas Types for Microwave-Based Head Imaging: Numerical Study

A design of proper antenna element for microwave-based head imaging or brain stroke detection, respectively, is a crucial challenge in process of MWI system designing. The main aim of this contribution is to compare dielectric sensitivity of three different antennas types namely bow tie antenna, slot and waveguide. A numerical model of simplified rectangular head phantom and spherical stroke phantom in COMSOL Multiphysics were created. It was observed transmission coefficients S21 between each of antennas couple depend on different stroke phantom type (HEM or ISCH) and its diameter. The greatest change of S21 represented the greatest antenna sensitivity for given scenario. The waveguide antenna shown the least sensitivity at all and non-consistent behaviour due to simulated scenarios. The most sensitive antenna on change of dielectric parameters was bow tie antenna, but only for scenario with HEM stroke phantom placed in head model. The most consistent behaviour proved slot antenna and due to this fact is for us most suitable for microwave-head imaging application.