Design of Ultra Wideband Antenna Array for Microwave Tomography

Microwave tomography is a classical approach for non destructive evaluation. Microwave tomography has many biomedical applications such as brain imaging, temperature sensing in different biological tissues and breast cancer detection. In a microwave tomography system, numbers of radiators are used to transmit microwave signal into an object under test and the scattered fields are recorded. The collected data is used to quantitatively reconstruct the dielectric profiles of the object under test through inverse scattering mechanism. It has been shown that by using wide band data, highly stable and high resolution reconstructions can be obtained. Lower frequency components provide stability of the reconstructions, while higher frequency components contribute to the resolution. Accordingly, ultra wideband antennas are required in UWB microwave tomography systems. In addition to ultra wide bandwidth, the antennas in a microwave tomography system should be easy to model with computational program. In this thesis Printed elliptical monopole antenna (PEMA) is investigated for microwave tomography. It is a multi resonant antenna with simple structure and yield ultra wide bandwidth. The performances of a single antenna and an antenna array are studied. The reflection coefficients of the antenna, mutual coupling between antennas and energy distribution in the near field are obtained by means of simulations in CST microwave studio. The simulation result shows that reflection coefficients of the designed antenna are below -10dB over the entire frequency band of interest (1-4.5GHz), mutual coupling between antennas at different locations are below -20dB over the entire frequency band of interest and the designed antenna also has good electric field distribution in an array configuration which makes the radiated power concentrating in the imaging region. These results indicate that PEMA is a potential antenna for microwave tomography applications.