The generation of ultra-wideband (UWB) pulses is a challenging problem that involves generating pulses with fast rise times on the order of 100 ps and voltages of more than 500 kV. Pulsewidths from 130 ps to a few nanoseconds (ns) are possible. A critical step involves switching high voltages with precision. The use of both gas and oil for the switching medium has been accomplished with varying results. The Air Force Research Laboratory (AFRL) is pursuing both media in the gas-switched H-series of pulsers and in studies of oil switches that promise good performance in compact packages. We are also pursuing solid-state switched systems that have demonstrated the potential for use in compact systems and in transient antenna arrays with steerable beams. The paper reviews recent progress in fast, high voltage switching and UWB transmitter development. These UWB pulsers and antennas have the potential for use in transient radar, target identification, and communications.