Burst Of Electrical Energy High-power Ultra-wideband Pulse Generator

The ultra-wideband (UWB) electromagnetic pulse technology is one of the most important and vigorous developing research fields for potential applications ranging from transient radar systems to high power jammers. However, the military application of UWB pulsers is limited by the fact that they have to depend on the ground DC power supply as their primary energy source. Therefore, the purpose of the dissertation is to design a completely self-contained UWB pulser that can operate without laboratory DC power.Useful electrical pulses of a few hundred kilowatts lasting for several microseconds may be obtained by the depolarization process of PZT95/5 ferroelectric ceramics. To date a detailed theory has not been developed for the electrical response of the shock depolarization of ferroelectric ceramics due to the complicated electric-dynamics nature of the process. Taking account of the dielectric relaxation, finite resistance and the shock wave traveling effects, a new physical model of PZT95/5 subjected to depolarizing shock wave was suggested. The predictions from the model in cases of short circuit, resistive, capacitive and inductive loads have a good agreement with our experimental results. The maximum output current on a 60uH inductive load was 1660A, and the maximum peaking voltage on resistive and capacitive loads was over 100kV in our experiments.Pulse transformer is an important device in the field of pulse power technology. In this work, the transmitting characteristics of transformer on various kinds of loads were investigated, and an oil-filled compact pulse transformer was designed. From experiments, the parameters with primary inductance 2.578,H, secondary inductance 167.710uH, and coupling coefficient 0.7238 were obtained.Pulse conditioning systems, especially sub-nanosecond switches, are a major component for UWB generation. The factors affecting the pulse rising time were analyzed in detail. Using an equivalent circuit model, the limit to the achievable rising time with spark technology was calculated, and a pulse conditioning system consisting of coaxialtransmission line and sub-nanosecond switches was designed and built.The measurement of ultra-short pulses is another problem in the field of pulse power technology. The factors that affect the frequency response of a capacitive divider were studied carefully. A coaxial voltage capacitive divider with an umbrella probe and a low-voltage circuit was presented. Experiments shown that the frequency response of our probe is better than others of such dividers.Finally, a compact UWB pulse source composed of PZT95/5 ferroelectric ceramic, a 50 coaxial transmission line charged by a pulse transformer, a peaking-chopping switch, a coaxial matched load and a pulse diagnostic system was built and tested, which can produce pulse voltage on a matched 50 load with peaking voltage of 100kV, rising time of 870ps, falling time of 670ps, and FWHM of 1.410ns. The remarkable merit of our UWB pulser is that it is a completely self-contained device working without laboratory electrical power supply.