Due to the increase in the threat of attacks with high-power electromagnetic (EM) pulses, there is great interest in metallic enclosures with high shielding effectiveness (SE). Necessary technological apertures in these enclosures reduce their effectiveness. Understanding the penetration and internal propagation of the high-power EM pulses into an apertured enclosure is fundamental to assessing the EM SE of the enclosure. In the present paper, results of the numerical simulations of development of the EM field in a shielding enclosure with aperture after the interference of a subnanosecond high-power EM plane wave pulse of the parallel polarization (having the duration of 0.3558 ns and the amplitudes of the electric and magnetic fields of 10⁶ V/m and 2.6 × 10³ A/m, respectively) are presented. The results obtained include 3D and 2D images , vector maps of the EM field developed inside the enclosure, and time-varying distributions of the electric charges formed on the inner walls of the enclosure. They revealed the mechanism of formation of the EM field inside the enclosure caused by the subnanosecond high-power parallelly polarized EM pulse. The EM field formed in the enclosure with aperture has the form of the electric and magnetic field interference structures. They are a superposition of the incident EM pulse field, which entered the enclosure through the aperture in the way described by the geometrical (ray) optics, the electric field generated by the electric charges formed on the aperture edges and inner sides of the walls of the enclosure, and the magnetic field generated by the surface current formed on the aperture edges and on the inner walls of the enclosure. The amplitudes of the electric and magnetic fields of the strongest EM interference structures decrease non-monotonically to about 0.7 × 10⁵ V/m and 200 A/m at t = 5 ns. We found that the points in the enclosure are subjected to the disturbance of a long series of subnanosecond EM pulses, which we have called internal EM pulses. The amplitudes of these internal pulses are lower than those of the incident EM pulse. Nevertheless, they can pose a severe EM hazard inside the enclosure due to their large number (about 900 internal pulses in 30 ns). This means a fundamental change in the character of the EM disturbance caused by the subnanosecond pulse when the enclosure with aperture is used as a shield.

The paper presents the static characteristics of the SiC transistor SJEP170R550 offered by SemiSouth obtained from simulations using JFET model built-in in PSPICE. Values of the model parameters were estimated using MODEL EDITOR, as well as procedure described in the literature. Simulation results were verified experimentally by comparison of results of measurements.

The paper deals with the problem of modelling and analyzing the dynamic properties of a Junction Field Effect Transistor (JFET) made of silicon carbide. An examination of the usefulness of the built-in JFET Simulation Program with Integrated Circuit Emphasis (SPICE) model was performed. A modified model of silicon carbide JFET was proposed to increase modelling accuracy. An evaluation of the accuracy of the modified model was performed by comparison of the measured and calculated capacitance–voltage characteristics as well as the switching characteristics of JFETs.

In the paper, the results of experimental verification of the macromodel of UJN1208K JFET transistor made of silicon carbide fabricated by United Silicon Carbide, are presented. The macromodel form dedicated for PSPICE program is available on the manufacturer's website. The accuracy of the macromodel have been evaluated by comparison of selected calculated and measured static characteristics and C-V characteristics of the considered transistor. The influence of ambient temperature on the characteristics of the transistor has been evaluated, as well.

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informuj?ce swoich czytelnik?w o najnowszych osi?gni?ciach naukowych i nowoczesnych rozwi?zaniach technicznych w Polsce i na ?wiecie, popularyzuje problemy techniczne oraz poszerza wiedz? i kultur? techniczn?.