Most of the shallow buried object detection techniques by ground penetrating radar (GPR) use a monostatic type radar system. The shallow target is difficult to be detected by the conventional GPR due to its low range resolution. Recently, we have developed GPR system based on single-plate monopole antennas operating in the frequency range between 1 GHz and 20 GHz. A total of seven monopole elements have been used to form an antenna array. The antenna and the array have been designed and simulated using CST microwave studio. Their impedance and radiation characteristics have also been simulated and measured. By using the designed antenna array, the GPR system has been constructed. The developed GPR system is able to acquire, save and analyse the data measured in frequency domain. Common source or wide-angle reflection and refraction (WARR) technique has been used for acquiring and processing the data. This technique is effective for the rejection of the ground surface clutter. The system has been tested in the laboratory. It shows its ability to detect metallic objects by using A-scan technique. Furthermore, we could localize a mine-like target buried in dry soil by applying the B- scan technique. Further details of the antenna simulation results and the application of the system in buried object detection will be discussed.