In this work, a complete microwave imaging system is designed and implemented for the reconstruction of breast tumor images. An UWB Vivaldi antenna is used in the bandwidth of 2-6 GHz to detect and localize the small tumors. The prototype hardware setup uses two Vivaldi antennas, one as transmitter and other as receiver for scanning. The distance between phantom and antennas is kept almost 20 cm. The scattered signals from the high contrast objects emulating the tumor characteristics have been processed through an open-source imaging algorithm, known as MERIT, to construct the image. To get the best results, images are constructed by comparing different algorithms and the varying number of channels. Simulated and measured results are successfully verified for different locations and sizes of conducting objects in a given imaging domain. The proposed system can be used for practical applications in biomedical imaging, especially for the detection of breast cancer at early stages.