Design of a Second-Derivative Gaussian pulse generator

Based on step recovery characteristics of stepped recovery diode (SRD) at reverse biased, a Second-order Derivative Ultra-wideband (UWB) Gaussian pulse generator is designed in this paper. Compared with previous generators based on SRD, a novel structure is adopted in the proposed one. The generator is composed of a shunt SRD, a series SRD, 3 RC networks and a short-circuited microstrip stub. In the proposed generator, the RC networks substitute for DC bias, the shunt SRD works as edge sharpener while series SRD generates short gaussian pulse, and the short-circuited micro-strip stub is utilized for shaping the second-order derivative pulse. The circuit is simulated by Advanced Design System (ADS) and fabricated. Measured results indicate that the pulse duration is about 800ps, and the peak-to-peak magnitude is 1.2 volt. Good symmetry has been shown in the measured pulse, and the ringing level is approximately -16dB.