This paper has reported a microwave imaging system employing a monopulse radar technique to eliminate adverse effects of strong reflection from the air-imaged body interface. This technique is realized using a newly constructed ultra wideband twoelement probe antenna fed by a 180° hybrid. The validity of the proposed system has been verified via full-wave EM simulations. Using the signal data obtained from the outof-phase fed UWB probe and by applying a confocal image reconstruction algorithm, the presence of a 9mm-diameter cylindrical target inside the 100mm diameter container filled with vegetable oil has been detected by just visual inspection of the produced image.