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Military systems are exposed to electromagnetic fields that are originated internally or externally during the whole operational life cycle. Military systems should perform their critical operational missions without any functional/performance degradation. In the case of military systems, due to the complexity of the complete vehicle electronic system architectures, electromagnetic compatibility requirements...
Signal penetration into missiles through nose cone and apertures is critical for electro-optical guidance systems, navigation equipment and control of explosive ordnance. Penetrated signals are relatively small but hard to simulate by known computational methods. To corroborate simulation results, we created a scaled version of a missile and placed wire antennas inside this mock missile. The prototype...
The use of electromagnetic shielding materials continues to grow in terms of research and application at various areas. In this paper, shielding effectiveness measurements are conducted to investigate the behavior of three different materials against electromagnetic fields. These materials are copper wire mesh, galvanized wire mesh, and aluminum plate. The purpose of using wire mesh structures is...
To support EMC test and measurements a single band chiral metamaterial absorber is suggested in this study for EMC absorber solutions. We analyze a novel chiral metamaterial absorber composed of crescent shaped split-ring resonators at the X-band (8.2–12.4 GHz). To supplement proposed absorber, different loss tangent (δ) values are also considered. Reflection and absorption spectra illustrated high-performance...
In this study, we designed multi and wide band frequency monopole antenna, consisted of FR4 as a substrate with thickness of 1.6mm. The radiating element is printed on a truncated metallic ground plane. Proposed antenna operates in UMTS and WLAN wireless communications applications at 1.9 GHz and 4.9 GHz respectively. The antenna was applied on FR4 plate with the dimensions of 42 × 42 × 1.6 mm3. This...
Magnetic field immunity tests are performed in laboratories in Screen Chambers (SC) in accordance with the standard IEC/EN 61000-4-8 by using a 1 m × 1 m loop antenna. However, the EMC tests of the Equipment Under Test (EUT) sometimes cannot be carried out in laboratories due to several restrictions. In case of EUT with large dimensions, high power consumptions and/or auxiliary devices which are attached...
Periodic moment method (PMM) is a useful tool to solve electromagnetic (EM) scattering problems for periodic structures. Double integrals over the cross section of the reference element are performed in the spectral domain formulation. Cross section of reference element of two-dimensional periodic structures; such as wedge absorber, is divided into different shape of cells to obtain scattering behavior...
In this study, a frequency selective surface consisting of open ring resonator arrays on glass substrate is proposed for filtering TM-polarized 2.6 GHz frequency band by using equivalent inductance and capacitance expressions and full-wave electromagnetic simulation. The FSS is evaluated for different permittivity, strip and gap width as well as strip length and periodicity values and the transmission...
Technological improvements and dense use of wireless systems has led to an increase in exposed electromagnetic radiation (EMR) levels in recent years. The effects of these EMRs on the population have not been completely characterized despite intense research on this topic. For this reason accurate evaluation of EMR levels in the environment have become essential. Therefore, this study aims to determine...
Evolution of modern communications and radar systems have steadily increased the demand on modelling the propagation effects with real world scenarios for various signal types. The main purpose of this research is to create a flexible, generic and realistic Radio Frequency (RF) environment simulator including both radar and communication signals. Software defined radio (SDR) platform has been utilized...
A pulse transmitter operating at VHF band has been designed using a pulse generator circuit and a pulse amplifier. The pulse generator circuit has been built using commercially available digital logic integrated circuits by taking advantage of the propagation delay characteristics. The pulse generator circuit produces a very short pulse in the order of several nanoseconds which is amplified by an...
Emanations from the information technology equipment may contain classified information being processed by the device. Shielding is one of the important techniques used for TEMPEST precaution and shielded window films can be viewed as the specific intent to prevent classified information processed within a building/area from being intercepted. The purpose of this work is to investigate the effectiveness...
In this study, metamaterial absorber structures that operate in the mid-wave infrared (MWIR) region are presented. The advantage of the design stems from the high absorptance in the region of interest and the ease of fabrication. Fabrication stage is facilitated by large in-plane geometric dimensions of the metamaterial pattern and small thickness of the full absorber geometry.
This paper presents a study of the Characteristic Basis Finite Element Method (CBFEM), which is an advanced numerical method that can be used in EMC applications. The CBFEM is a non-iterative domain decomposition technique employing characteristic basis functions, and it provides considerable reduction in matrix size and convenient parallelization, both of which make use of direct solvers in a memory-...
Crosstalk is an important phenomenon for both EMC (electromagnetic compatibility) and TEMPEST. Crosstalk prevention requirements for cables can be found in many different standards. This work aims to analyze the crosstalk effects on power cables. For this purpose, initially the theoretical background of crosstalk between cables will be discussed. Then, simulations that are performed will be analyzed...
Understanding the nature of electromagnetic (EM) wave interference is essential in EMC engineering. EM wave interference mainly includes the diffraction and fringe effects. This paper aims to visualize the diffraction and fringe effects using the canonical wedge structure.
This paper presents design and simulation results of the cylindrical axial virtual cathode oscillator which is frequently used to damage electronic equipment by generating High Power Microwaves (HPM). Simulations are performed in MAGIC Tool Suite which uses FDTD-PIC algorithm to solve particle beam and field interactions. During the design procedure, AK Gap is changed from 5 mm to 12 mm and the scaling...
Ground penetrating radar (GPR) is an electromagnetic sensor based on the ultra-wideband radar technology that can also be used for through-the-wall (TTW) target recognition. Search for the presence of designated targets hidden behind the walls, such as stationary or moving human bodies or certain types of weapons, is addressed in various critical applications; in rescue missions after earthquakes...
We present a novel multigrid approach for the shape optimizations of corrugated metallic sheets by using genetic algorithms (GAs) and the multilevel fast multipole algorithm (MLFMA). The overall mechanism is obtained by an efficient integration of GAs and MLFMA, while the optimizations are improved by applying multiple grids at different layers. We show that the multigrid approach provides more effective...
It is well-known that a resonating metamaterial can interact with other nearby resonating metamaterials. If this coupling is strong enough, it may change resonant behaviour of overall metamaterial structure composed of individual metamaterial resonators. Therefore, defining each part separately, especially the coupling factor, simplifies the electromagnetic compatibility (EMC) problems. In this study,...
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