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In this study, a novel ultra-wide band (UWB) antipodal Vivaldi antenna with three pairs of slots designed to be used as a sensor in microwave imaging (MWI) system for breast cancer detection. The proposed antenna operates in UWB frequency range of 3.05-12.2 GHz. FR4 was used as a dielectric material and as a substrate for forming the antenna that has a compact size of 36 mm x 36 mm x 1.6 mm. Frequency and time domain performance of the proposed antenna have been investigated and results show that it meets the requirements for UWB radar applications with linear phase response, nearly constant group delay, ultra-wide bandwidth and directional properties at most of the operating frequency. Then, the capacity of the proposed antenna as a sensor was tested in a monostatic microwave breast imaging system that was developed in the CST Microwave Studio (CST MWS) simulation software. In the simulation application, 50 mm radius hemi-sphreical breast models with different densities were formed and 2 mm diameter spherical tumor was placed inside them. Antennas were positioned cylindrically around the breast to send Gaussian pulse and collect backscattered signals. After signal processing steps, tumors was screened at correct positions with high resolution. Finally, a monostatic radar based breast phantom measurement system developed to automatically scan the breast phantom in the prone position. To perform experimental measurements, an electrically and anatomically realistic homogeneous breast phantom with tumor inside was fabricated. Screening of the tumor at correct location indicates that the proposed antenna and the microwave imaging system developed using this antenna are suitable for the detection of breast cancer at the early stage.

Meme kanseri tümörlerinin erken evrede görüntülenmesinde kullanılan mevcut görüntüleme tekniklerinin bazı dezavantajları, radar tabanlı mikrodalga görüntüleme yönteminin güçlü bir alternatif olarak doğmasını sağlamıştır. Bu yöntemde, verici antenden gönderilen Gauss darbe sinyali memeye nüfuz etmekte ve geri saçılan sinyaller alıcı anten tarafından kaydedilmektedir. Kaydedilen bu sinyaller, çeşitli sinyal işleme aşamalarından geçirildikten sonra görüntüye dönüştürülmektedir. Görüntünün çözünürlüğünü belirleyen en önemli faktörlerden biri de antenin bant genişliğidir. Bant genişliği, verici anten tarafından gönderilen Gauss darbe sinyalinin süresini belirlemektedir. Bant genişliği arttıkça Gauss darbe sinyali kısalmakta, bant genişliği azaldıkça darbe sinyali uzamaktadır. Bu çalışmada 3-11 GHz arasında farklı bant genişliği kombinasyonlarının tümör görüntüsünün çözünürlüğü üzerindeki etkileri araştırılmıştır. 3-5 GHz,

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