Development Of A Transient Electric Field Sensor

A nuclear explosion can radiate an electromagnetic pulse (NEMP) through theinteraction of γ-rays and air molecules, and it is one of the main hazard approaches bynuclear weapons. Usually NEMP has high field strength and fast rise time. Theseyears, with the development of information technology, more and more high powerelectromagnetic (HPEM) environment has been paid attention to. HPEM includeslight EMP (LEMP), high power microwave (HPM), ultra wideband (UWB),electrostatic discharge (ESD), high power switching EMP and so on. Protection fromHPEM has become an important basic issue in developed countries. Accuratetime-domain measurement for transient field is one of the key technologies.Nowadays, there are many kinds of electric field sensors. However, foreigntechnology goes far ahead of that in China, and that severely limits the developmentof some related research.The sensor in this paper has a monopole antenna. A high input resistance circuitis connected to the antenna to satisfy time-domain and frequency-domainrequirements. Then the electric signal is modulated to an optic signal that can betransmitted by optic fiber without interference of electromagnetic field around. In theend a photoelectric conversion is conducted and the field signal can be observed onthe oscilloscope. The whole system should satisfy time-domain andfrequency-domain requirements. The conversion between electric and optic signalsshould avoid substantial loss of signal data. A sensor was designed and tested with anEMP simulator. Through the research and study of test result, we realized that thebandwidth, response time and some other parameter meet the requirements forrelevant research. Besides, some deficiencies were realized and should be improvedin the following researches. At the same time, different sensors were comparedthrough some test result, and their characters and suitable applications were studied.