Ultra-wideband pulse generator with picosecond fall time and tunable amplitude

Generating ultra-wideband pulse is a key technique for subsurface ground penetrating radar. By sharpening the transition time of pulse, the high frequency component can be improved, which contributes to the increase of bandwidth. In this paper, a compact pulse generator based on avalanche transistor and step recovery diode (SRD) is studied. Load resistor in the Gaussian pulse circuit is optimized to increase the pulse amplitude. In addition, the performance of output pulse is studied for different stage of shaping circuit. Experiment results show that transition time of the pulse is reduced by increasing stage of shaping circuit properly. As a result, we demonstrate a pulse with transition time of 200ps, full width at half maximum of 500ps, and amplitude of 43V.