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We study the scattering of a vegetation canopy consisting of a large number of thin cylindrical scatterers using Numerical Maxwell Model in 3D Simulations (NMM3D). The full wave approach for solving Maxwell equations is based on the Foldy-Lax multiple scattering equations (FL) combined with the Method of Moments for bodies of revolution (BOR). The accuracy of the method FL-BOR is first validated by...
A fully coherent snowpack scattering and emission model is developed by numerically solving Maxwell's equations over the entire snowpack on a bottom half-space. The scattering matrix of the snowpack is directly obtained including both amplitude and phase. Both bistatic scattering coefficients and brightness temperatures of the snowpack are derived from full wave simulations. Simulation results demonstrate...
In this paper, we report a new approach of modeling anisotropy snowpack using bicontinuous media [1, 2]. We then extract the uniaxial effective permittivity of the anisotropic bicontinuous media by numerical solving Maxwell's equation in 3D (NMM3D) over spherical samples of the media extending a few wavelengths. The effective permittivity is then extracted by comparing the coherent scattering field...
In this paper, we study backscattering from the ocean using 3D numerical simulation of Maxwell's equation (NMM3D). Previously we used NMM3D to compute backscattering and emissivity of rough soil surfaces for active and passive microwave remote sensing of soil moisture [1, 2] at L, C, X and Ku bands. The computed results were in excellent agreement with measurement data for co- and cross-polarizations...
The partially coherent approach of dense media radiative transfer (DMRT) has been extensively applied to study the wave propagation and scattering inside dense media such as terrestrial snow [1–5]. In the DMRT partially coherent approach, the coherent part is obtained by solving Maxwell's equations over several cubic wavelengths of statistically homogeneous snow volume to compute the phase matrix,...
Combined active and passive microwave remote sensing of vegetated surfaces is of great interest and importance given the increasing number of active and passive satellite microwave missions and datasets available for studies in land surfaces for application in hydrology and terrestrial ecology [1]. For many years, passive microwave retrieval algorithms for satellite missions such as AMSR-E, SMOS,...
The distorted Born approximation (DBA) combined with the numerical solutions of Maxwell equations (NMM3D) has been used for the radar backscattering model for NASA's Soil Moisture Active Passive (SMAP) mission. The models for vegetated surfaces such as wheat, grass, soybean and corn have been validated with the Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12) data. In this paper...
Snowpack consists of ice grains that are densely packed in the wavelength scale at microwave frequencies so that the coherent microwave interactions among the ice grains are important in microwave signatures. We have used Numerical Maxwell Model of 3D simulations (NMM3D) of random media / discrete scatterer to study such interactions. In the partial coherent model of Dense Media Radiative Transfer...
We study the accuracies of numerical simulations of scattering by random rough surfaces in 2D based on the Nystrom method. The method is shown to be accurate for a large range of permittivities as well as for large roughness and fine scale roughness. We compared Nystrom method with impedance boundary conditions (IBC) method using both parameters of soil surfaces and ocean surfaces. In some cases,...
In vegetated surface scattering, the physical values of optical thickness and scattering albedo both increase with frequency. At C-band, because of the attenuation due to large optical thickness, the distorted Born approximation gives negligible values for the surface scattering term and double bounce term. Because of the smallness of these two terms, the distorted Born approximation gives results...
We apply computer generation of anisotropic bicontinuous media with different vertical and horizontal correlation functions. We then use NMM3D (Numerical solutions of Maxwell equations in 3-Dimensions) to calculate the uniaxial effective permittivities and the effective propagation constants of V and H polarizations. The co-polarization phase differences (CPD) between VV and HH backscattered signal...
Scattering matrices (SVV, SHH, SVH, SHV) are calculated from numerical 3D solutions of Maxwell equations (NMM3D). Using the simulated scattering matrices, we compute the polarimetric speckle and the coherency matrix for Pol-SAR applications. Results from NMM3D are examined by the comparison with theoretical distributions, including amplitude, phase difference, and amplitude ratio. Surface roughness...
We have studied the electronic transport characteristics of nanowire field effect transistors (NWFETs) made from phase-pure wurtzite (WZ) and zinc blende (ZB) InAs nanowires (NWs). The electronic characteristics were obtained at temperatures between 4 and 300 K. The ZB NWFETs exhibited a greater sensitivity to the surrounding atmosphere than WZ NWFETs. The WZ NWFETs had a higher mobility than ZB NWFETs...
In this work, we use a mostly analytical approach of Foldy-Lax multiple scattering equation method to efficiently model and solve physical/electromagnetics properties of the structures of SIW based devices and 3D IC in chip-package-board system which include multiple vertical and horizontal interconnects. We decompose the modes effects inside the target structures into modes of cavity with multiple...
Subwavelength imaging has been reported for a layer of plasmonic thin film. In this paper, we investigate the enhancement of the sub-diffraction-limit imaging using subwavelength surface roughness. Full wave simulations are carried out based on Lippmann Schwinger equation with linearized scattering potentials. Progresses in experiment are also reported.
Most of the via modeling methods assumed that only the TEM mode which is the fundamental mode can propagate due to the thickness of substrate being electrically small, and all the higher order waveguide modes and anisotropic modes decay rapidly along the radial direction thus they can be ignored. However, for high speed chip and die level packaging system, due to the interested frequency range is...
Snow and Cold Land Processes (SCLP) is a decadal satellite mission of NASA with both the passive microwave sensors and the active Synthetic Aperture Radar (SAR). Bicontinuous / DMRT model is used to model the brightness temperature and radar backscatter. We apply the approach to the ground measurement data of NoSREx campaign which has multichannel measurements in both active and passive remote sensing...
In this work, we use a mostly analytical approach of Foldy-Lax multiple scattering equation method with a recent major improvement, 1D technology, to efficiently model and solve physical/electromagnetics properties of the structures of SIW based devices and 3D IC in chip-package-board system which include multiple vertical interconnects. We first use MoM with 1D discretization to obtain the surface...
This paper presents a hybrid multilevel UV method with the fast far field algorithm for the random rough surface scattering calculations. In the MLUV, a pre-ranked sampling algorithm is used to further compress the UV matrix pairs. To further improve the efficiency of the algorithm, from the second and third coarsest level, a hierarchical FAFFA is employed to further enhance the efficiency of the...
In this paper, a new efficient methodology is used to model dense via arrays in 3D integrated circuit and package system, which also can include the layout of multiple vias sharing the same antipad. In order to accurately calculate all the effects of high order waveguide modes and azimuthal modes for complete signal integrity analysis of multiple closely spaced vias, we make use of transformation...
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