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In this paper A wideband radar cross section (RCS) reduction structure applicable to rod-like targets on the dielectric surface is studied. The influence of dielectric surface lie chiefly with narrow frequency band with no more than 5dB. In addition, as for the typical frequency point at 9GHz, the discrepancy of RCS sweep of the multistep cylindrical structure near normal incidences between with and...
This study discusses about the findings of a radar cross section (RCS) and Specific Absorption Rate (SAR) study of human head at 0.9–2.45 GHz based on full-wave numerical model simulations. The homogeneous SAM head were used to simulate the human head. We analyze the RCS and SAR of the human head as a function of aspect angle and frequency, drawing important conclusions in terms of the magnitude of...
In this paper, we propose a blind Volterra series based nonlinear equalization (VNLE) with low complexity for the nonlinear distortion mitigation in short reach optical carrierless amplitude and phase (CAP) modulation system. The principle of the blind VNLE is presented and the performance of its blind adaptive algorithms including the modified cascaded multi-mode algorithm (MCMMA) and direct detection...
In this paper, theoretical investigation about the nonlinearity distortion caused by the chromatic dispersion and square law detection is presented. Then Volterra series based nonlinear equalizer (VNLE) is proposed for CAP modulation short reach optical transmission. The coefficients for high order Volterra kernels in the VNLE are investigated and the number of nonlinear memory length is optimized...
The spectra of wind waves in lake Michigan was introduced for computing the electromagnetic scattering from the rough lake surface. In addition, the JONSWAP ocean spectrum is used in this article to generate numerical data for the scattering of random rough sea surface. The normalization RCS (NRCS) is computed as a function of the incidence angle. It is found that the NRCS of the scaled lake surface...
Setting a proper number of antenna elements in arrays as a DDM unit, an artifice of DDM application for extremely big arrays is presented to balance the required RAM and calculating time for solving in each DDM unit and information exchange among different units. With this method, for array with hundreds of elements, both of the RAM and time consumed could be reduced, while the big arrays which are...
The near-field scattering of complex targets is a very useful characteristic parameter for theory analysis and measurement. With the MLFMM, the near-field scattering of a typical ship have been simulated to analyze the near-field scattering characters of the ship in free space in different detecting distances and frequencies. And the results show that with reduction of range, the difference between...
Babinet's principle is applied to three kinds of metamaterial designs, including SRR structure, S structure, and single side paired S-ring. The retrieval results for each complementary unit cell group are obtained based on their S11 and S21 simulation data. By means of comparison, the complementary metamaterial's negative permittivity happens at the same frequency band, where is supposed to be a magnetic...
The near-field measurement and near-far field transformation of microwave scattering of a plate at different distances are presented. With the measurement, the near-field scattering of a metal plate have been obtained in agreement with MLFMM simulation. In addition, based on the transforming method from near-field to far-field of microwave scattering, far scattering results were derived from the near...
In this paper, RCS reduction based on metamaterial absorber (MA) structure is investigated in microwave frequency band. The measured results for conducting plane and dihedral angle reflectors coated with metamaterial (MM) layer and FR-4 dielectric layer are presented, which is carried out in an open area test site. Significant RCS reduction by the MA structure is achieved. For the planar MA, the maximum...
In this paper, we build an improved model of microwave scattering for two dimensional fractal sea water. Based on the double Debye dielectric model, both the geometrical fractal characteristic and permittivity characteristic of sea water is more strictly considered. In our model, the effect of salinity and temperature on the microwave scattering by sea water is added on precisely. Finally, the calculated...
The near-field scattering of ships is a very useful characteristic parameter for theory analysis and measurement. With the MLFMM, the near-field scattering of a typical simplified ship have been simulated to analyze the near-field scattering characters of the ship in free space in different detecting distances and incident angles. And the results show that with reduction of range, the difference between...
In this work, a human head from nuclear electromagnetic pulse (NEMP) is simulated by using CST program for the analysis of SAR at 1MHz, 10MHz, 50MHz. The human head model is homogeneous and simulated with the brain equivalent material. And the NEMP is described by the second double exponential pulse shape with some characteristic parameters. From these results, we find that while the frequency increase,...
In the paper, the radiation characteristic of dipole array along end-fire direction is researched. The electric field intensity values in end-fire area are calculated using FEKO under different situations. It is also analyzed how metal plate and scanning angle influence end-fire area. Besides, the whole dipole array is divided into several subarrays. Through comparing radiation characteristics of...
The aim of this study is to establish the quantitative expression about flat-roofed width in near-field scattering of conductor flat. At the basement of phenomenon analysis, we have made a theory derivation of the flat-roofed width function of some parameters, such as distance, size and etc. In addition, the precision of predicted results have been verified by physical optics method. From the expression...
Abnormal phenomenon on shielding effectiveness (SE) of metallic enclosures with one rectangular aperture when illuminated by the oblique and normal incidence vertical polarized plane wave has been studied by using MoM and FIT techniques. To the best knowledge of authors, the similar phenomenon and analysis for it has not been investigated. The work shown that the usual assumption about the normal...
The prediction from classic prediction equation on EMI is revised with GTD which can quantify analysis the effect against transmission on obscuration from superstructure of ship. In addition, quantified diffraction factor and diffraction loss are obtained. It can correct the defect of traditional method which ignores the obscuration from superstructure of ship (or only qualitative analysis). And the...
This work simulates the shielding characteristic of a typical decay waveguide window for EMP. In the past, most researchers on electromagnetic protection have mainly focused their attention on the aperture coupling on the rectangular cavity. In contrast, the focus of this paper is not on it, but rather on the shielding characteristic of a typical decay waveguide window for EMP. The effect on EM coupling...
In designing of anechoic chamber with higher quality, when requirements of quiet zone index are higher, it must use the geometrical theory of diffraction instead of the geometrical optics for accuracy. The utilities of the theory in design have been discussed in this paper. Besides, in analysis of reflectivity versus incident angle of absorbing materials, it's used to use linear interpolating method...
The vibration between shipboards on ship-sea integrational electromagnetic Scattering is presented. The numerical results of the integrational target have been obtained using MLFMM in High Frequency, computing the RCS as a function of the elevation angle and vibration angle. It has been observed that as for two different polarizations, the RCS of the integrational target have raised a dozen of dBsm...
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