Wyniki 1-2 spośród 2 dla zapytania: authorDesc:"Yahia ACHOUR"

Nanosecond EMP simulator using a new high voltage pulse generator DOI:10.15199/48.2017.10.07

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The design of reliable electrical systems is not a simple task, especially in some sensitive domains which demand high-security level like aeronautics and aerospace or for those working in very severe conditions such as the military equipment. Therefore, several standards and norms have been elaborated in order to normalise the tests’ conditions that the system should sustain in order to be approved, in particular, those tests connected with the electromagnetic compatibility (EMC). In our case, we are interested in the checking of the susceptibility of a designed system to the electromagnetic radiated pulses (EMPs) like those created by nuclear explosions or some electromagnetic weapons in order to confirm its ability to work in electromagnetic hostile environments. For that purpose, it’s very important to reproduce, in the lab, artificial conditions where the tests could be carried out. The presented paper is a part of a general project of developing a test bench (simulator) capable of producing EMPs. It’s devoted to explain the primary designed solution, present the constructed prototype, discuss the experimental results and measurements done in the lab and comparing them with the results obtained from simulation. In this work, we mainly focus on the connection between the high voltage pulse generator and the antenna, which can be done using different alternatives such as a direct connection without any intermediate or using some kind of pulse forming networks or transmission lines to adjust the impedance between the generator and the antennas. The chosen solution depends on several parameters like the generator impedance, the distance between the generator and the antennas, the frequency range (i.e wavelength)...etc. The second point discussed in this paper is the measurement of the radiated EMP.using a fast free field D-dot probe, which is a convenient way to measure the high amplitude electrical field[...]

D-dot, B-dot Data Processing of Fields Generated with Broadband Pulsed Antenna DOI:10.15199/48.2019.11.29

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During our attempt to build a jamming system based on electromagnetic pulse (EMP) system [1], we had to measure the radiated electrical and the magnetic fields using fast D-dot and B-dot probes [2]. These measurements were necessary to confirm that the jammer is really radiating and also to get more information about the frequency range and the power density of the generated waves. After recording data, we faced two major problems. The first one is that the two curves do not start at the same time. This difference is caused by the delay in the optical links which are not the same for both sensors and additionally by the propagation time in the conditioning circuit. The second problem was to find the ratio between the two signals, because the irregular form of the signals made it difficult to describe them in a parametrized form. The first problem was solved with calculating and maximizing the correlation between the two. The second issue was approached as a single variable optimization problem, in which we tried to minimize the distance between the electrical field data and the magnetic field data. If there is a propagation, this optimization variable would fit to the intrinsic impedance of the air for the far field mode. Recording data at different distances from the antenna allowed us to analyze the attenuation of the near field static component and the building up of the far field. Description of the EMP generator and the measurement setup The experimental setup consists of two main parts: a high voltage pulse generator connected directly to a broadband antenna, which contains the Electromagnetic pulse (EMP) generator, or in other words, the jammer. In the second part, the radiated field is sensed and recorded via free field D-dot and a B-dot probes located nearby the antenna. The probes are connected to fast oscilloscope with a 40 GS per second using an optical link. The oscilloscope is located inside a shielded cont[...]

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