A Marx-Based Gaussian Monocycle Pulse Generator With Low Ringing Level for Ground Penetrating Radar Applications

Abstract

The Gaussian pulse generator is the core component of the pulse ground penetrating radar (GPR) system, which requires high amplitude, narrow pulse width, and low ringing levels. Marx circuits are widely used to generate Gaussian pulses. However, due to the complex pulse-forming process, the high-amplitude pulses generated by conventional Marx circuits suffer from oscillation and severe ringing. In this article, a refined model of the Marx circuit based on lossy transmission line theory is proposed, which effectively reduces the oscillation and ringing level of the generated Gaussian pulses. Furthermore, a monocycle pulse-shaping network is proposed based on the short-circuit stub. The unipolar Gaussian pulse is converted into a Gaussian monocycle pulse for antenna radiation. Waveform experiment results show that the peak-to-peak value of the output pulse is 428 V, the pulse width is about 0.8 ns, and the ringing level is low at about 9%. The profile imaging result of the sand tank detection experiment further shows that the generated high-quality Gaussian monocycle pulse can provide good detection performance of underground buried targets for the pulse GPR system.