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The following topics are dealt with: environmental electromagnetic compatibility; RFID technology; Internet; mobile wireless network; quality of service; wired network; ad hoc network; sensor network; mobile communication; wireless communication; communication theory; communication software; information infrastructure; information security; communication protocol; signal processing; signal coding;...
The paper deals with the human exposure assessment to extremely low frequency (ELF) electric field due to overhead power lines. The formulation is based on a realistic human body representation taking into account different conductivities for various tissues inside the body. In particular, the influence on conductivity variation to the induced current densities and electric fields is investigated...
In this paper, the human exposure to HF radiation is analyzed using the simplified human equivalent antenna model featuring analytical and numerical approach, respectively. Namely, the human body is represented by an equivalent receiving straight thin wire antenna vertically located on the perfectly conducting (PEC) ground plane. This thin wire representation of the human body is based on the corresponding...
In this paper, the human exposure to electromagnetic field radiated from the communication transmitter on the ship deck is analyzed. Two simplified models of the human body exposed to the electromagnetic radiation, the parallelepiped model for the calculation of SAR and cylindrical model for the calculation of the current induced in the human, are used. The fields were measured on 36 different locations...
This article presents different electromagnetic irradiation scenarios of a heterogeneous human heart placed in the field emitted by a dipole antenna. An anatomical model of the human heart was proposed. Specific absorption rates were calculated using a numerical software based on the finite difference time domain method. Several positions and frequencies for the radiation source were considered and...
In this paper the lightning current function proposed in IEC 62305-1 is approximated by a linear combination of exponential functions in the time domain, which will afterwards be analytically transformed into the frequency domain. The unknown coefficients of the exponential approximation are computed using the least squares method. Lightning current function in the frequency domain can be used for...
The aim of this paper is to present a new cfor multi-conductor transmission line (MTL) analysis in frequency-domain. The proposed model based on the finite element method (FEM) is compared with traditional technique such as the modal method. Applying analytical solution of the telegrapher's equations we can construct the finite element local system of equations and apply standard assembly procedure...
For different values of the decay constant in the modified transmission line model with exponential decay (MTLE) and for different channel heights the results for lightning electromagnetic field (LEMF) at different distances from the channel-base are presented in this paper, so as for the spatial and temporal current distribution along the channel. The decay constant influence on LEMF above perfectly...
Elucidation of the biological effects of the radio frequency (RF) electromagnetic fields has been investigated for decades but it is still not clear weather the observed effects are only due to hyperthermia or non-thermal effects exist as well. In this work, the effect of radio frequency (RF) radiation on protein expression in earthworms E. foetida using two-dimensional protein gel electrophoresis...
The optimized version of the indirect time-domain method based on a numerical electromagnetic code (NEC) used in combination with fast Fourier transform (FFT) is presented. One of the most serious limitations of the indirect time domain methods when compared to direct time-domain methods, relative inefficiency, is tackled by applying an optimization during transfer function calculation. The optimization...
This paper presents a brief review of the most important methods available for the grounding grid analysis. This includes numerical methods intended for the grounding grid direct current, time-harmonic current and transient current energization. Emphasis will be given to the methods involving transient grounding grid analysis. Available numerical methods will be surveyed according to the implemented...
Classical Fresnel-Arago interference laws are describing an energy redistribution in the space and they are approving that orthogonal polarized waves cannot have the interference. However, this fact is correct only for full power (energy). The point is that arbitrary polarized waves are described not only full energy. Full polarization description of these waves can be made only with the use so-called...
Due to its approximately hemispherical radiation pattern, the quadrafilar helical antenna is commonly used in a wide variety of radio systems, especially in satellite communications. This paper is focused on appropriate design of this antenna in order to obtain the desired performance, like cardioid shaped radiation pattern and excellent circular polarization with a high axial ratio. Also, the antenna...
The paper presents the simulation analysis and comparison of two commercially available shipboard cylindrical trihedral radar reflectors. The reports found in literature indicate that this type of radar reflector provides very poor radar visibility. Therefore, detailed analysis was carried out taking into account various heeling angles of radar reflectors and various azimuth angles of incident plane...
Mast-mounted shipboard VHF half-wave antenna along with the sailboat conducting structures was simulated in NEC. Antenna radiation pattern was analyzed based on the simulation results. The effects of ground plane (sea), mastantenna interaction and mast-sailboat interaction were investigated. Resulting vertical patterns in all cases have many distinct narrow lobes, contrary to the free-space antenna...
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