This research article presents a proficient, convenient, and low-cost monostatic radar-based microwave imaging (RBMI) technique for the breast tumor detection. For this, a compact cubical dielectric resonator antenna (DRA) with impedance bandwidth of 8.3 GHz (ie, 4.3-12.6 GHz) has been simulated using CST V 0 17. In proposed monostatic RBMI technique, the designed DRA is placed parallel to the breast phantom and rotated around it at an interval of 10 in elevation plane (0-π) and azimuthal plane (0-2π), respectively; first, without and then with tumor inside the breast phantom. Total 1080 back-scattered signals are recorded for the entire impedance bandwidth, and processed for microwave imaging. For the validation of results, fabricated antenna is rotated around the artificial breast mimic. The artificial breast mimic is made up from gelatin (skin), petroleum jelly (fat), and wheat flour (tumor). The backscattered signals from the artificial breast phantom have been recorded on the vector network analyzer model no. E5063A for both the cases that is, with absence and presence of tumor at different position and time intervals. The recorded S-parameters have been processed in two beam-forming algorithms; delay and sum (DAS), delay multiply and sum (DMAS). These signals are then converted into digital data and processed in the MATLAB, to visualize the 2D image of the scanned area to detect the breast tumor. By comparing the reconstructed images, it is concluded that the DAS algorithm provides just a clue about the presence of the tumor, but DMAS provides the accurate position and size of the breast tumor.