PROTECTION OF ELECTRONIC EQUIPMENT AGAINST NUCLEAR ELECTROMAGNETIC PULSE (NEMP)
HOSSAM aBD EL-FATTAH EL-SHIEKH;
Abstract
The waveform of the large altitudes EMP includes an. early pulse of high amplitude and short period, in addition to intermediate and late time pulses of progressively lower amplitudes and longer periods.
The NEMP can penetrate into systems through antennas, long and short
transmission lines, and through apertures in shielded enclosures. Peak currents of thousands of amperes may be induced in conductors. NEMP induced currents and voltages may cause upset in digital electronics, temporary malfunction of circuits and sensitive component damage.
Protection against NEMP includes the use of metal shields around electronic systems, proper grounding, the use filters on lines and the use of surge suppressors such as zener diodes. varistors and gas discharge tubes .
Penetration ofNEMP into shielded volumes containing apertures is investigated in the present work using the finite-difference time domain method .The characteristics of the penetrating field are considered for a cubic cavity with square and rectangular apertures. The resonant modes excited inside the cavity are determined through the FFT of the penetrating field. The effect of the cavity volume and aperture size on these modes and on the decay rate of the field inside the cavity is investigated. The dependence of the peak penetrating field on the dimensions of square and rectangular slots is considered in two cases, when the NEMP electric field is perpendicular or parallel to the slot. The effect of the aperture location is also considered. Finally, the current induced in a wire inside the cavity is investigated.
The NEMP can penetrate into systems through antennas, long and short
transmission lines, and through apertures in shielded enclosures. Peak currents of thousands of amperes may be induced in conductors. NEMP induced currents and voltages may cause upset in digital electronics, temporary malfunction of circuits and sensitive component damage.
Protection against NEMP includes the use of metal shields around electronic systems, proper grounding, the use filters on lines and the use of surge suppressors such as zener diodes. varistors and gas discharge tubes .
Penetration ofNEMP into shielded volumes containing apertures is investigated in the present work using the finite-difference time domain method .The characteristics of the penetrating field are considered for a cubic cavity with square and rectangular apertures. The resonant modes excited inside the cavity are determined through the FFT of the penetrating field. The effect of the cavity volume and aperture size on these modes and on the decay rate of the field inside the cavity is investigated. The dependence of the peak penetrating field on the dimensions of square and rectangular slots is considered in two cases, when the NEMP electric field is perpendicular or parallel to the slot. The effect of the aperture location is also considered. Finally, the current induced in a wire inside the cavity is investigated.
Other data
| Title | PROTECTION OF ELECTRONIC EQUIPMENT AGAINST NUCLEAR ELECTROMAGNETIC PULSE (NEMP) | Other Titles | حماية الاجهزة الالكترونية من النبضة الكهرومغناطيسية للانفجار | Authors | HOSSAM aBD EL-FATTAH EL-SHIEKH | Issue Date | 2001 |
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