Investigation Of High-Voltage Ultra-Fast Electromagnetic Pulse Radiation Characteristics And Experimental Rules

Ultra-wide band technology is widely applied in communications, radar, electronic countermeasure and other areas. High-gain ultra-wide band antenna has been one of key technologies for ultra-wide band high-power, which has very important research significance. Photoconductive Semiconductor Switch (PCSS) as a novel type of high-power ultra-wide band electromagnetic pulse emitter that it has incomparable advantages comparing with traditional switch. The range of its frequency is from ten to several tens of MHz and even tens of GHz, the relative wide of linear electromagnetic pulse is more than 25%, PCSS has high-gain output and can be excited by lower energy laser pulse, so that it became possible to make the all-solid state mini-size high-power ultra-wide band electromagnetic pulse emitter system. However, the radiation at nonlinear mode has not been reported, the theory of optically activated charge domain, what is used to explain the nonlinear mode, needs further improvement. Furthermore, the further research of laboratory effects on radiation is needed, the exact relationship among the switch gap, optical pulse width and the spectral distribution when the switches are working at linear mode.In this article, the mechanism and application of Semi-insulating (SI) GaAs PCSS generating ultra-wideband electromagnetic and test results were analyzed and studied. In this paper, we mainly comparative analyzed the time-domain characteristices and the frequency distribution characteristices of the ultralfast electromagnetic pulses by the ps laser pulse triggered SI-GaAs photoconductive switches with different gaps, Experimental data shows that smaller electron gap is beneficial to the radiation. And we come to a conclusion that the time-domain characteristices and the frequency distribution characteristices of the ultralfast electromagnetic pulses by the ns,ps,fs laser pulse triggered SI-GaAs photoconductive switch, The article indicates the output pulse band of frequency is mainly determined by the rise time and the fall time of the electromagnetic pulse. The narrower electrical pulse is, the wider distribution of the spectrum is. The high-frequency component of output electromagnetism pulse is determine by rise time of electric pulse, and the low-frequeucy component is determined by fall time. As well as, we analyzed the time-domain characteristices and the frequency distribution characteristices of the non-linear experiments by the ps laser pulses to trigger SI-GaAs photoconductive swithes. At the same time, the connection between the characteristic of time-domain and frequency were analyzed. The analysis indicate that the narrow gap switches make the radiate spectrum wider and radiate relatively high efficiency of electromagnetic pulse on the premise of that there is no loss of the rise time of electric pulse. At the same time, in this article, combined with the light-induced charge-domain theory, we supposed that non-linear pulse maintenance phase is formed by narrow pulse envelope and conduct a preliminary analysis of assumptions at the non-linear pulse radiation experiment.