Frequency and bandwidth agile pulser for use in wideband applications

We have developed an architecture to produce a wideband pulser that is tunable in the important parameters of pulsewidth, bandwidth, and center frequency. The pulser is based on a parallel plate Blumlein pulse-forming network (PFN) with a movable center (charge) conductor. When the center conductor is displaced from the ideal Blumlein position, the balance in the PFN is lost, resulting in a slightly ringing waveform that can be tuned. By selecting the amount of ringing, the output bandwidth of the PFN can be adjusted. Furthermore, by simply sliding the center conductor out of the PFN, the effective electrical length can be adjusted, allowing the fundamental period of the ringing waveform to be altered, thereby changing the center frequency of the output waveform. Our pulser is designed to operate in the range of 300 MHz to 2 GHz, but the architecture is scalable outside this range. In this paper, we present design and simulation results, low-voltage tests, and preliminary high-voltage (15-kV) data that is obtained with a pressurized gas trigatron designed specifically for this test fixture. The pulser is being designed for laboratory use in testing the effects of interaction of high-intensity wideband electromagnetic fields with small-scale electrical and biological systems.