A compact former of high-power bipolar subnanosecond pulses

The system comprises a nanosecond SOS-generator or the RAD AN SEF-303 pulsed power source that charges resonantly a short pulse-forming line (PFL) through a decoupling inductor, a peaking SG, an active converter, a matched load and several built-in voltage and current probes. The active converter comprises two SGs (chopper and peaker), an additional Ins PFL and a secondary decoupling inductor for resonant charging of the second PFL. The peaking SG and active converter are set in one body and operate in N₂ at pressure up to 6 MPa. Weighing less than 10 kg, the converter generates bipolar subnanosecond pulses having peak-to-peak amplitude up to 270 kV on a 46.6 Ω load at operation with Radan. The pulsewidth of each half wave of bipolar pulses on FWHM is 280 ps at the rise time of the first half wave of about 160 ps. The SGs´ gaps can be regulated without system depressurizing. Circuit analysis accounting for the distributed character of the components and numerous parasitic parameters is presented. Voltage measurement means, including several capacitive dividers, Rogowski coils, attenuators and connection cables, were time-domain calibrated using ultrafast high voltage solid-state pulsers. Waveforms probed at different locations of the pulser systems, from the SOS-generator and from the Radan to the load, are presented. The bipolar subnanosecond pulses had very stable rise, while the fall jitter was around 50 ps. The experimental results are in fair agreement with the simulation. Pulsers were tested with a TEM horn antenna. An effective potential of about 900 kV was obtained.