Transient High-power Electromagnetic Pulse Sources

As a new subject, photoelectron made up of optics and electronics has a great progress in recent decades. Especially the development of material technology for super shot pulse laser material technology lays a foundation to the development of the high-power instant electromagnetic supplier and switch technology. A critical step involves switching high voltages with precision. A Photoconductive Semiconductor Switch (PCSS) is a new kind of devices that are composed of photoconductive semiconductor and the ultra fast pulse laser. The most important attributes of photoconductive semiconductor switches (PCSS) are jitter free triggering, low inductance and capacitance, fast rise time, fast recovery time and high repetition rate than traditional switches. The discovery of III-V semiconductor such as GaAs not only can work under linear mode which after receiving a photon with given energy, a pair of electron and cavity is produced. But also they can operate in a nonlinear mode with high gain which can reduce the triggering optical energy by 3-5 orders of magnitude comparing to the conventional linear mode. This makes it realistically possible to realize the miniaturization,practicality and integration of the system of PCSS。So it will be applied widely in ultra-wideband source circuit.Ultra-wideband (UWB) sources and antennas are of interest for a variety of potential applications that range from transient radar systems to communications systems. The generation of ultra-wideband 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. The research of instant electromagnetic pulse is an advanced task of the electromagnetism, which can be widely used in many fields: ultra-wide radar, ultra-wide secrecy communication, high-power microwave and etc. The detailed analysis of the high efficiency propagation of instant electromagnetic pulse is presented in this paper. At the same time, the experimental result is given out.The author does much work on the physics mechanism of PCSS, calculate many parameter of the GaAs material through microcosmic statistics. There are many scattering mechanism in the material, such as ionized impurity scattering, deformation potential scattering, piezoelectric scattering and so on. Then the drift mobility and conductance in the case of different carrier concentrations can be got. The result of the calculation lays a foundation to the establishment of PCSS physics model under different work mode.The paper also introduces many experiments. Such as voltage transfer efficiency of linear PCSS, saturated optical energy and the resistance of PCSS without optic inspirited. The author proves that transient electromagnetic pulses could synthesize in phase perfectly through large-scale antenna array. The axial electric field intensity and energy density of antenna array measured in different conditions indicate that axial electric field intensity is proportion to the number of antenna elements and the energy density is proportion to the square of the number of radiation units.