Antenna Design For Microwaves Early Breast Cancer Imaging Using Time Reversal

This dissertation studies mainly about two different programs. The first program is about antenna design and its’ implementation for microwaves early breast cancer imaging using time reversal, particular consideration is giving to breast cancer imaging employing time reversal MUSIC; and then the second is about modeling some breast tissues mimicking phantoms to facilitate the experimental work intended for breast cancer detection as mentioned in the first program.In chapter one, a brief introduction on the problematic of breast cancer diagnosis followed by the risk associated to the disease and some information about the attention paid to this particular researching area are giving. Some information are giving such as the commonly used methods for early breast cancer imaging(advantages and limitations), the founding organizations and services. Typical research cases studies of the disease with estimated figures are mentioned. It is also clearly explained that an ideal imaging method should be cost-less; capable to identify and differentiate malignant from benign tissues; and also it should have high accuracy and good sensitivity.In chapter two, we have introduced the basic theoretical concept of microwaves for breast cancer imaging and its classification. By taking into account the methodologies used in the imaging system, it can be classified into three: passive, active and hybrid. Some imaging methods and techniques used for early breast cancer diagnosis are explained; a particular interest is granted to the use of time reversal MUSIC method(TRM) in cancer imaging. In addition, some applications of microwave imaging are mentioned.For chapter three, human breast tissues electrical properties, its anatomy and breast tissues mimicking phantom modeling are studied. Some types of cancers which could be found on women breasts are mentioned. An explanation showing the difference between the normal and cancerous tissues is provided. In this chapter the study involves also the modeling and the experimental implementation of the breast tissues mimicking phantoms. During the breast phantom modeling, some daily life use materials having different dielectric characteristics were considered and carefully mixed together in a controlled ratio in order the mimic the dielectric characteristics of the human skin, normal and tumor tissues, similar to that of the real breast tissues. The result shows that this goal has been achieved(dielectric constants relatively close to the real breast tissues are obtained). The difference in dielectric constant between healthy and cancerous tissues is explained. The experimental set up and measurement procedure(method and techniques) are explained in appropriate sections through the whole document. For a better understanding, some comparisons are conducted between the results obtained from simulation and measurement. Additionally, during this experiment all the materials used are non-toxic, very safe through physical contact even through inhalation.In chapter four, we have introduced the need of antenna design in microwave medical imaging, the software used through the design and experiment, the designed antennas structure and parameterization. The basic parameters characterizing antennas performance are explained, followed by antenna applications and propagation principles as well. The challenges in antenna design for medical imaging applications and the proposed solutions are giving in this chapter. The remaining sections of the chapter discusses about the current work done on the designed antennas: from the geometrical parameterization to the experimental implementation for breast cancer detection. T he simulated and measured results are giving with some comparisons.Regarding the antennas used in this dissertation, five different antennas have been designed: two UWB compact directional balanced antipodal Vivaldi antennas(BAVA) operating in the range of 0.7-3.1 GHz and 3.1-10.6 GHz, respectively; two UWB monopole antennas which operate in the range of 3.1-10.6 GHz(according to FCC) and one single frequency antenna design, operating at 2.45 GHz. The designed antennas are tested for microwave breast cancer detection with the use of time reversal MUSIC method. Simulated and measured results have shown good agreement. Good impedance matching is obtained for both designed antennas. High gain, good directivity and low cross polarization are achieved for the BAVA. One of the big advantages of the UWB monopole antennas is that a relative size reduction is achieved with no increment of the permittivity value or increasing the frequency. Various antennas which are used and / or have the potential to be used in medical imaging application are reviewed.After the antenna design and breast tissues mimicking phantoms modeling have been completed, simulation and experiments involving breast cancer detection were then conducted. The results obtained explain about the ability of the antennas to transmit and receive a narrow pulse signal in a short time period and also show a good estimation of the target location within the object under investigation. This is very important not only in breast cancer detection through medical imaging but also in security checking(i.e. in public places such as airports and train stations).The advantages and challenges of these designed antennas and breast tissues mimicking phantoms for microwave and medical imaging applications, particularly with the use of time reversal are detailed. Some possible solutions to overcome these challenges are suggested.At the end, in chapter five, we have given a general conclusion of the dissertation, explained the problems encounter trough this research and then suggested some points for further improvement.