REPETITIVE, ULTRA-WIDEBAND IMPULSE SOURCE DEVELOPMENT AT SANDIA NATIONAL LABORATORIES

Sandia National Laboratories has established a repetitive, ultra-wideband (UWB), impulse-transmitter development initiative. The development addresses impulse technology to support many ultra wideband experimental applications. The initiative may be divided into three elements, source development, antenna design, and operations. Under this program, four different sources have been developed with each source having its own particular set of parameters. In general, each source generates a narrow (2-11s FWHM) pulse with a very fast risetime (on the order of 250- pS). The output voltage, ranging from a few tens of kilovolts to 240-kV, is radiated by a wide-band antenna. Depending upon the source, repetitive operation from single shot to 5-kHz has been obtained with excellent reliability and repeatability. This presentation will focus entirely on the spark-gap based designs. There are four existing pulsers of the SNIPER (Sub-Nanosecond LmEulsE Radiator) class. All the present pulsers use a hydrogen-thyratron based modulator, an oil-filled Blumlein, and an oil peaking switch. Powers exceeding one-gigawatt are routinely generated. The frequency spectrum of the radiated pulse from these sources extends from 100-MHz to 3-GHz. This technology appears to be extendable to at least 10-gigawatts.