The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A multipath model of UWB pulse propagation in the indoor environment is addressed in this paper. The simulation utilizes the principles of geometrical optics (GO) for direct and reflected paths' tracing and time domain technique for describing the transient electromagnetic field reflected from wall, floor, ceiling, and objects. The closed-form time domain analytic solution for UWB impulse signal reflection,...
To determine whether exposure to electromagnetic pulses (EMP) emissions results in behavioral effects and evaluate memory function of rats pups. The Wistar rats, either male or female, were divided randomly into two groups respectively: control (CTR) and 104 pulses (G1). Then G1 group was exposed to EMP of 146. 5 kv/m field amplitude and 104 pulses. For the day of exposure till 3 months later, they...
How to overcome the instability of the two-layer dispersive media mie series formula is firstly discussed when the electric size of sphere is large. Then, the radar cross section of an impedanced-matched, ideal, homogeneous double-negative (DNG) metamaterials sphere is computed. The backward radar cross section of the DNG media sphere adds up to zero. The radar cross section of metallic sphere covered...
To investigate effects of microwave radiation on levels of microelement in bone tissues of mice. Microwave with a frequency of 2450 MHz and a power density of 10 mW/cm2 was used. Variation of levels of microelements and effect of drugs were observed. And thereby bioeffects of microwave on mice were studied. In microwave group bone tissues contents of microelements Ca and Zn dropped significantly (p<0...
The article abstractly describes some points of methods on further improving of the spectrum efficiency. At first, the author introduces the current challenges facing spectrum management, spectrum circumstance and the traditional regulatory framework of doing this in China. Then the importance of raising the spectrum efficiency and some technical methods are analyzed in the article. The strategy of...
The characteristics of transient voltage, current and grounding resistance of a spokewise grounding electrode is investigated based on field measurements. The grounding electrode is composed of 8 reinforcing steel bars with diameter of 10 mm, every bar with the length of 2 m, and is buried at the depth of 0. 6 m from the ground surface. A pulse discharge from a high-voltage capacitor is applied at...
The shielding effectiveness of aperture arrays with different shapes is calculated and analyzed. The influence of the spaces between the adjacent apertures is analyzed. The results show that: when the spaces between the adjacent apertures is larger, the coupling of the adjacent apertures can been neglected , the contours of shielding efficiency of the transmission line method agrees with that of TML...
In this paper, the E-field distribution in a waveguide partly filled with t issue-simulating liquid at mobile communications frequencies is presented. For the E-field probes calibration in the tissue-simulating liquid, a standing open rectangular waveguide partly filled with tissue-simulating liquid is used in which the E-field can be calculated analytically from input power measurements. It is desirable...
This article first introduces the improved theory of transmission line method (TLM), which is used to analyze shielding effectiveness of rectangular enclosure with improved aperture model. The calculations show that the contours of TML shielding efficiency is in agreement with the that of FDTD calculation. Then we expand the fundamental formulas to deal with the cases of multi-holes, and arbitrary...
Electromagnetic shielding is the technique that reduces and prevents coupling of undesired radiated electromagnetic energy into equipment, so as to enable it to operate compatibly in its electromagnetic environment. Usually, the frequency considered for electromagnetic shielding design is above 10 kHz, but the lower frequency for some special demand is 50 Hz or even 0.01 Hz sometimes. This paper mainly...
A new digital filter design method based prewarping is proposed , the digital filter frequency characteristic very well approximated to the original analog filter one' s, and two design examples of the BW (butterworth) filter and the elliptic filter are presented. The results of computer simulation are consistent with the theoretical analysis.
Due to the non-flat amplitude-frequency characteristics of antennas used in EMC measurement, measuring results can not accurately present the real levels of radiations. So, transfer functions for frequency-domain compensation of antennas, should be adopted to rectify the radiations levels. Vector fitting is a popular iterative rational approximation technique for transfer function in the frequency...
As a new measuring method for the frequency range 1 GHz to 18 GHz, amplitude distribution probability (APD) method had been formally written into CISPR 16-1-1 Ed. 2: Specification for radio disturbance and immunity measuring apparatus and methods in 2005. For the traditional EMI receivers that are employed widely in most EMC test labs, additional measuring apparatus were necessary to implementing...
It presents a measurement of pulsed electric field by way of portable measurement system for the shielding effectiveness of pulsed electric field, tn order to research the influence of bonding method of cross points of reinforced grids and the size of reinforced grids, three bonding methods and two types of reinforced grids' size are evaluated in this measurement. Then the results of experiment are...
In this paper, numerical calculation method based on analytical formulas and FDTD are studied. A physical model for nature lightning is built in this paper, the lightning channel as a long ling wire, lightning current' s double exponential pulse time domain waveform. The numerical method from dipole formula is obtained by scattering lightning current at time and space, With finite difference time...
After reviewing the calculation of lightning radiation electromagnetic field above perfect conductor ground, the expression of the lightning radiation field above lossy ground is derived rigorously in this paper. Based on above two cases, the effect of the height of lightning channel, observation point height, and soil resistivity on the lightning radiation magnetic field are analyzed respectively...
A fast algorithm is introduced in this paper for three-dimensional conducing medium. The algorithm applies suitable approximation and parallel computation to MoM so that the computer memory and run time will be reduced significantly. Finally, we calculate a three-dimensional thin lossy plate as an example to approve the accuracy and efficiency of our algorithm.
In this paper, the method to locate ADSS on power tower is based on MOM. Firstly, possible positions for ADSS cable suspending are obtained based on the IEEE P-1222 standard and distribution of potential around the transmission line and tower. And subsequently, analysis of electric field along the ADSS cable is performed to choose the position where the electric field intensity is lowest as the final...
When a log-periodic antenna array is measured on a three-axis revolving table, because the revolving table is made of metal, it must have some influence on the antenna array' measured results. This paper is to discuss the effect of revolving table on the radiation pattern of antenna array. By using software based on the moment method, the revolving table and the log-periodic antenna array are modeled...
High-speed railway is the trend of our national railway. Research of the radio wave propagation is very important for the development of railway wireless communication system. In the paper, the simulation model of channel is formed using the theory of sine superposition. The parameters of the model are confirmed using the method of equidistance. Then, on the base of this channel, the characteristics...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.