3-D microwave scanner for biomedical applications: A preliminary prototype

This paper introduces the prototype of a scanning system operating in the microwave range 0.5-4 GHz with strong potential for biomedical applications such as breast cancer detection or to assess shape-discontinuity in bones. A fully automated scanner was designed to reduce mechanical uncertainties and data acquisition time. Accurate positioning and synchronization with data acquisition enables a rigorous proof-of-concept for the microwave imaging procedure. The system can remotely control two printed antipodal Vivaldi antennas that scan a phantom across a set of positions arranged in cylindrical coordinates. For antenna miniaturization and improved coupling, the antennas and their interface and the phantom are immersed in a coupling medium that presents electric properties similar to adipose tissue. The system performs automatically both the antenna positioning and data acquisition and post-processing. In the current version the reflection coefficients are measured by a Vector Network Analyzer (VNA). But the integration of dedicated chipboard attached to each antenna to replace the VNA and speed up data acquisition is on process. Without any difficult a priori antenna characterization, the system is to detect, in the phantom, enclosed regions with distinctive dielectric contrast.