Movement effect on electrical properties of UWB microwave antenna during breast tumor diagnostic scanning

Utilization of the UWB antenna as a main device for breast cancer detection is an interesting research topic in the last five years. This detection method is well-known as Ultra Wide Band (UWB) Microwave Imaging. In this paper, a stairs-shaped microstrip antenna was successfully designed to satisfy the UWB technology standard. The numerical evaluation of the antenna performance shows that the antenna is well operated in the frequency range from 3.5 to 7.2 GHz (computed using Ansoft HFSS v13) and the frequency range of 4 - 7.3 GHz (computed using CST Microwave Studio). In the numerical experiments to verify the actual operation of the constructed breast cancer detector the homogeneous breast phantom was generated in close proximity of the antenna system at various different locations. The more interested study was performed by altering the antenna position to cover the whole surface of breast phantom with a variety of tumor size. It is obviously that the antenna system movements do really affect the electrical properties of the medical diagnostic instrument such as radiation pattern, current distribution, VSWR and S11. There are two main antenna parameters continuously recorded as an impact of the instrument movements and of very interested to be analyzed i.e. the resonance frequency and the return loss. The study also found that the effective angle to perform the breast cancer scanning task is about 0 degrees and 15 degrees, respectively. Outside the range the instrument has a poor scanning capability.