Requirements analysis and modelling of an antenna element for breast cancer microwave imaging
Malignant tumour diagnostics plays a significant role in the ability of contemporary medicine to treat cancer illnesses because early stage cancer can be treated successfully by well developed conventional techniques. Microwave imaging is new and is still largely undergoing research. It exploits significant differences in the conductivity between malignant tumours and healthy breast tissue. One of the biggest challenges in such systems is a significant level of undesired signal reflections from the skin and fat layers, especially in the case of detecting small tumours. One of the possible ways to overcome the current challenges in microwave imaging/detection is to use microwave holography and 3-D imaging. This method would involve an array of antennas and processing algorithms to reconstruct an image using the phase information of backscattered signal. The aim of the proposed research is to analyse the physical requirements for such a technique. To formulate requirements for an antenna element antenna setup requirements have been considered. Such an approach let to address some of known issues related to human tissue properties and microwave propagation in it. From the other side quality of the reconstructed image would depend on the working frequency and placement of antenna elements. Thus the distribution of the antenna elements in the antenna array has been considered and the appropriate configuration proposed. The middle frequency was selected as trade-off between attenuation properties of the human tissue and desire to get best resolution. The antenna element design was selected on the base of the requirements. Modelling of the antenna element was provided with open source software. Results of initial modelling were fairly close to the requirements. However performing several modifications with antenna dimensions and placement of the feeding point allow improving the model, particularly its reflection coefficient. An eight of antenna elements were manufactured and measurements for the single and pair antenna element have been provided. This research has achieved its objectives successfully and identified areas for future development.