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Based on the Equivalent Current Theory of optical waveguide coupling, the electric field distribution of grating structure and notch groove slit are derived. Beam divergence angle with different grating notch groove and light intensity of non-uniform array antenna structure are numerical simulated. Beam light field background comparison diagram with different notch groove current amplitude and the...
The broadband and high rate advantages of Terahertz (THz) wave communication attract tremendous attention of many researchers, and the study of the THz sources and detectors are more popular in recent years than previous. The study on the propagation characteristics of THz wave in troposphere is relatively rare, and it is necessary due to the rapid development of the THz devices. The content of water...
The trend of higher frequency band than microwave and millimeter wave used in various regions, ultrafast broadband communication and high accuracy imaging application, etc., calls for the development of the Terahertz (THz) technology. Unlike the hot concentration on the study of the THz sources and detectors, the study of the propagation characteristics of THz wave in the atmosphere is relatively...
Terahertz wave propagation property, which contains the voltage fluctuation, the reflection effect, the dispersion effect, multipath effect, attenuation effect, etc., in random medium such as the atmosphere is one of the most essential problems to consider in the application of Terahertz wave. The absorption due to the molecules in atmosphere of the Terahertz wave is significant in the absorption...
There are important effects on the electron equipments for the variations of ionosphere, such as it can induce shortwave communications quality decline even interrupted, navigation signal scintillation and error increase, space aerocraft orbit changes, hardware charging up and proton events etc. In a word, studying ionospheric characteristics is indispensable to study the ionospheric effects on electron...
The influence of zenith angle on the scattering properties by the spheroid particle upon wafer is discussed in this paper. Taking the advantage of the Bobbert-Vlieger (BV) theorem, the scattering model between wafers and spheroid particles is established. The scattering process is analyzed and the scattering coefficients are derived by using of the vector spherical harmonic function. The differential...
During artificial ionospheric modification and convective electric field, plasma is in an iopsided state, and the velocity distribution of particles is non-Maxwellian. Application of the empirical Bump-on-tail distribution of electrons in incoherent scatter spectra of plasma is studied in this paper. Features of the distribution function are discussed. With Bump-on-tail distribution function, numerical...
Based on the multi-scatter propagation model of Monte Carlo, an improved geometric model is proposed. The model is ameliorated by using the point probability method. Comparison is made between the multiple scattering propagation models and the single-scatter propagation model in calculation time and relative error. The effect of complex weather, stumbling block and the transmitter and the receiver...
The issue of seismo-ionospheric anomaly is noticeable increasingly. In this paper we use a model for the generation of the electric field in the ionosphere by an external current on the Earth's surface to calculate the electric field in the ionosphere over the forthcoming earthquake preparation area. At the selected parameters the horizontal electric field in the ionosphere reaches ~10mV/m, while...
Electromagnetic scattering of a plane wave with circular polarization from a uniaxial anisotropic sphere with arbitrary primary optical axis is researched. The incident circular polarization wave is expanded in terms of the spherical vector wave functions (SVWF's) in arbitrary primary optical axis coordinate and the expansion coefficients are derived by superposition of the expansion coefficients...
A major earthquake (M=7.3) occurred in Haiti (18.5°N, 72.5°W) at 21:53 UT on 12 January 2010. On the basis of regular GPS observations from the International GNSS service (IGS) network, Global Ionospheric Maps (GIMs) of total electron content (TEC) from 27 December 2009 to 16 January 2010 were analysed. It was shown that there was a significant enhancement of TEC around the epicentre on 11 January...
An analytical expression for the fourth order moment of the plane wave scattering from two-dimensional randomly rough surface with small roughness is presented based on the Kirchhoff and physical optics approximation. The fourth order moment has been simplified to get the two-position and two-frequency mutual correlation function. With the incidence wavelength 1.06 mum and different root-mean-square...
An improved average technique, restraining the oscillation of the time-domain integral equation (TDIE), is presented in this paper. The method provides a much more stable explicit marching-on-in-time (MOT) solution to arbitrary conducting objects. The examples demonstrated the superior stability of the proposed average technique.
The light scattering problems of dust particles cluster was simulated with a diffusion limited aggregation (DLA) model of the fractal theory using FDTD method. The simulation study with a random two and three dimensional diffusion was carried out. The effect to the degree of polarization with wavelength was given and discussed for dust particles cluster.
Studying on electromagnetic scattering by particles plays an important role in atmosphere monitoring, space remote sensing and some other fields. Scattering by a homogeneous sphere located in a 2D Gaussian beam is discussed in the paper. Expansions of cylindrical vector wave functions in terms of spherical ones are introduced simply. With the expansions, the beam coefficients in a spherical coordinates...
According to strong fluctuation theory, the Mellin transform techniques is applied to the wander effects of the collimating laser beam propagation in atmospheric turbulence on the slant path considering different height of drone and different outer-scale of turbulence. Applying the ITU-R turbulence structure constant model which is altitude dependent to calculate the wander variance. The conclusions...
An image recovery method based on adaptive wavelet filter, DCT filter and iterated denoising, is introduced into the recovery of radio interference on backscatter ionogram. The algorithm is testified by ionogram of Australia, and PSNR of this method is up to the order of 40 dB. The method in this paper has advantages over traditional method, and a better statistical performance is obtained for backscatter...
Light scattering provides a powerful tool for bare substrate and thin films characterization. Angle-resolved light scattering has been used to quantify the surface roughness of optical components. However, light scattering properties are different between opaque substrate and transparent substrate because angle-resolved light scattering is affected by the contribution of both interfaces of the transparent...
A modified and simplified five-parameter model is presented based on the Torrance-Sparrow model. Multi-angle bistatic data of the surfaces of various materials and roughness are fitted by using this model. The results of five-parameter model are in good agreement with the measured data, and closing to the results of two-dimensional bidirectional reflectance distribution function (BRDF) models. The...
The spectral bi-directional reflectance distribution function (BRDF) of some satellite coating material and solar plane samples in the band from 380 to 780 nanometres is measured with relative measurement in the laboratory. The spectrum BRDF which can characterize the spectrum reflectance property of samples is obtained by weighting the measured spectral BRDF by the spectral irradiance of the incident...
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