## 1 Introduction
The ambient temperature is isolated and the dipole antennas are fixed to the tissues in the breast model and heat is given, and the tissues are raised above normal temperature levels. Thus, tumor detection is performed by creating thermal models [33; 34; 35]. The RMWBI system is non-contact and does not require an invasive procedure for measurement. It also does not require heat insulation in the measurement environment. In the RMWBI system, the antennas used as sensors send pulse signals towards the target (breast phantom) and collect the reflected signals back. In these systems, different antenna types are used according to need. These are resonant, patch, bowtie, monopole, dipole, Vivaldi, and other antenna types [29; 36; 37; 38; 39]. Among these antenna types, the Vivaldi antenna stands out with its advantages [40]. Vivaldi antennas are ideal for RMWBI since they provide high gain, bandwidth, high directivity, and efficient impedance matching [41; 42]. Compared to other techniques such as patch or dipole antennas, the Vivaldi antenna shows superior performance in terms of optimum accuracy and tissue penetration [43; 44; 45]. Vivaldi antenna has been used as a sensor in many studies in the literature [40; 46; 47; 48; 49; 50; 51; 52; 53]. Various materials such as epoxy-FR4, polycarbonate, polyimide, rubber, and silicone are used as substrates in Vivaldi antenna design. The use of the FR4 substrate is ideal for the design of Vivaldi antennas due to the desired wide bandwidth, impedance matching, stable radiation values, high gain, good directivity, compact size, cheapness, and easy availability [54; 55; 56]. All of the signals received back from the target with the RMWBI system are signals reflected from breast tissues and other environmental noise. In order to obtain a tumor response, it is necessary to eliminate the unwanted portions of the signals reflected back from the breast. The most difficult part in the filtering of the reflected signals is the elimination of noise [57]. For this purpose, filtering techniques are used to obtain tumor response [58; 59]. The adaptive Wiener filter has been proposed as an effective algorithm to remove noise and this method has been used in studies in the literature [53; 57; 60; 61; 62]. In addition to filtering algorithms, image formation algorithms are also very important in tumor detection. Algorithms such as rotation subtraction, signal filtered merging, singular value decomposition, and hybrid approaches have been proposed, but their performance also depends on anatomical features [63; 64; 65; 66]. DAS and DMAS are the reference image formation algorithms for RMWBI systems [67; 68]. The DMAS imaging algorithm is an extended version of DAS with higher contrast resolution [69; 70]. The DMAS algorithm provides high resolution, making it ideal for tumor detection [53; 67]. In the RMWBI technique, breast phantom tissues to be used as target objects must be designed in accordance with the electrical properties of the real breast. The design of artificial breast phantom tissues in simulation and experimental environments according to appropriate electrical properties has been presented in scientific studies [71; 72; 73]. The study conducted by [PERSON] et al. continues to be the main reference due to its electrical properties close to real breast tissues and the long life of the breast phantom [53; 72]. There are studies in the literature that use breast phantom for breast tumor detection [48; 50; 53; 74; 75; 76; 77; 78; 79]. The radiation performance of Vivaldi antennas can be improved by changing some of their geometrical properties. The antenna geometry was optimized using particle swarm optimization and the gain and directivity of the Vivaldi antenna were increased by adding side slots [48; 80]. Double petal was used to reduce the low frequency [49]. When the antenna dimensions were calculated according to the FR4 based transmission line model, approximately 60 mm \(\times\) 55 mm was obtained.