Determination of Shielding Effectiveness of a Subnanosecond High-Power EM Interference by an Enclosure with Aperture Using Time Domain Approach

The most likely intentional high-power electromagnetic (EM) interference, threatening the operation of technologically advanced electronic infrastructure, will have forms sub- and nanosecond ultra-wideband (UWB) pulses, several hundred pulses attenuated sinusoids, microsecond sinusoidal pulses. protection objects against EM is provided by different types metal enclosure shields with technological apertures, inside which sensitive can be placed. These apertures allow external interference to penetrate into enclosure, making shielding imperfect. has been mainly assessed based on so-called effectiveness (SE) parameters. SE parameters (SEe SEm for electric magnetic fields, respectively) are useful designing comparing shields. In relatively small enclosures, recently become subject interest, studied long transient longer than 150 ns, i.e., whose duration much time that pulse takes pass enclosure. this work, we dealt an ultrashort pulse, was shorter transit through subnanosecond UWB example such a pulse. For performance size numerically (W:H:D = 455 mm:50 mm:463 mm) aperture (W:H 80 mm:30 mm). Gaussian distribution fields amplitudes 106 V/m 2.68·103 A/m, respectively, applied in study, had 0.0804 ns (FWHM). This means about 18 times it (equal 1.5 ns). Our numerical simulations interior were performed domain using commercial code CST Microwave Studio. First all, time-domain resulted 2D 3D images vector maps visualized temporal spatial development field caused incident interference. associated proceeded two phases: first form waves later as pattern, traveling forth back between front rear walls. Due energy loss aperture, suffered tendency evenly distributed over throughout entire decreased 30 within 90 ns. Despite loss, developed existed at least 1000 (i.e., demonstrated calculation). Apart from visualization, simulation enabled easy tracking behavior selected points Such showed each point passed series called internal (at repeatedly influenced 500 many these only (3–5) lower amplitudes, may cause severe shows substantial change nature plane wave when given not shielded (a single strong pulse) repetitive weaker pulses). With dependence obtained calculation determine SEe function time. way, evaluation local (for enclosure) performed. Moreover, calculated various times. maps, shown paper, give more global view properties aperture. all advantages use approach studying case interferences.