# A Modified Compact Flexible Vivaldi Antenna Array Design for Microwave Breast Cancer Detection
###### Abstract  
In this paper, a compact, flexible Vivaldi antenna is designed, and an array of nine identical antennas of this type is used as a microwave breast imaging model to detect cancerous tumors in the multilayers phantom model presented in this paper. The nine-antenna array is used to measure the backscattering signal of the breast phantom, where one antenna acts as a transmitter and the other eight antennas act as receivers of the scattered signals. Then, the second antenna is used as a transmitter and the other antennas as receivers, and so on till we have gone through all the antennas. These collected backscattered signals are used to reconstruct the image of the breast phantom using software called \"Microwave Radar-based Imaging Toolbox (MERIT)\". From the reconstructed image, the tumor inside the breast model can be identified and located. Different tumor sizes in different locations are tested, and it is found that the locations can be determined irrespective of the tumor size. The proposed modified Vivaldi antenna has a very compact size of 25 \(\times\) 20 \(\times\) 0.1 mm\({}^{3}\) and has a different geometry compared with conventional Vivaldi antennas. The first version of the antenna has two resonant frequencies at 4 and 9.4 GHz, and because we are interested more in the first band, where it gives us sufficient resolution, we have notched the second frequency by etching two slots in the ground plane of the antenna and adding two rectangular parasitic elements on the radiating side of the antenna. This technique is utilized to block the second frequency at 9.4 GHz, and, as a result, the bandwidth of the first resonant frequency is enhanced by 20% compared with the first design bandwidth. The modified antenna is fabricated on Polyimide flexible material 0.1 mm thick with a dielectric constant of 3.5 using a standard PCB manufacturing process. The measured performance of this antenna is compared with the simulated results using the commercially available simulation software Ansoft HFSS, and it is found that the measured results and the simulated results are in good agreement. flexible antenna; Vivaldi antenna; breast imaging; microwave imaging; cancer detection Article  
A Modified Compact Flexible Vivaldi Antenna Array Design for Microwave Breast Cancer Detection  
Aydin, A.M., A.M.  
methods are one of the promising techniques for early breast cancer diagnosis [7]. At microwave frequencies, the contrast between the electrical properties of cancerous cells and those of healthy breast tissue is significant. Several experimental studies of dielectric properties of healthy and malignant breast tissues have been reported in the literature. In [8], a large-scale study, with 319 measurements on freshly excised breast tissue specimens to experimentally determine the ultrawideband microwave dielectric properties of a variety of normal, malignant, and benign breast tissues, measured from 0.5 to 20 GHz, is reported. The analysis showed that the contrast in dielectric properties between malignant and normal adipose-dominated tissues in the breast is considerable, as large as 10:1. Moreover, the contrast in the microwave-frequency dielectric properties between malignant and normal glandular/fibroconnective tissues in the breast is no more than about 10%. In [9], experimental measurements of dielectric properties of normal and tumorous tissues on more than 220 tissue samples were performed in the frequency range of 0.5 to 50 GHz. The results showed that the mean values for tumorous and normal tissues are separated from each other at all frequencies. Moreover, the normal tissue samples were divided into three subgroups based on their adipose component percentage. It has been found that as fat content decreases, the average dielectric properties rise significantly between groups. An average contrast in dielectric properties of malignant and healthy tissues of 8.4:1, 2.2:1, and 1.4:1 exist for low-adipose, medium-adipose, and high-adipose tissues, respectively.