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In this paper, the Broadband Green's function with low wavenumber extraction (BBGFL) is applied to modeling of traces connecting vias in printed circuit boards, particularly arbitrarily shaped power/ground planes. The proposed method is a hybrid technique based on mode decomposition: BBGFL is used to fast compute the vias in power/ground planes, method of moments (MoM) is used to calculate the impedance...
In this paper, we develop broadband Green's functions for inhomogeneous waveguide with arbitrary shaped boundary using Broadband Green's function with low wavenumber extraction (BBGFL). The waveguide consists of two dielectrics and a linear eigenvalue problem is obtained for the modal solution by using surface integral equations and broadband Green's functions of the reference waveguide. The modes...
The Green's function is an important physical concept and is key to the formulation of integral equations. In the past, the free space Green's function and the Green's function of an empty lattice were used to study wave behavior in periodic structures such as metamaterials and photonic crystals. In this paper, the Green's function of periodic scatterers are calculated and next used to formulate integral...
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...
Effect of roughness on forward physical model for Brightness Temperature of Antarctic ice sheets is presented. The Antarctic ice sheet which is characterized by layers of ice with permittivity fluctuations in addition to random rough interfaces. In order to investigate effect of roughness on brightness temperature, we only consider top 20 layers of ice sheets rough and all other layers with flat interfaces...
We applied the Numerical Maxwell Model in 3 Dimensions (NMM3D) to radar scattering from ocean surfaces at L band. The formulation is based on the PMCHWT surface integral equation which uses separate Green's functions for air and ocean permittivities. The Sparse Matrix Canonical Grid (SMCG) is used to compute Method of Moments (MoM) solutions in conjunction with Rao-Wilton-Glisson (RWG) basis functions...
We have been engaged in Numerical Solutions of Maxwell equations (NMM3D) for more than fifteen years [1-2]. In this paper, we report on the recent progress of NMM3D on random rough surfaces and discrete random media and their applications in active and passive microwave remote sensing. The random rough surface models were applied to soil surfaces and ocean surfaces. The discrete random media models...
We validate an absorption based radar retrieval algorithm of snow water equivalent (SWE) using X- and Ku-band backscatter with airborne SAR data. The bicontinuous dense media radiative transfer (Bic-DMRT) model is first applied to generate a look-up table of snow properties against backscattering at X- and Ku-bands. In the retrieval algorithm, the background scattering is subtracted from the total...
The Ultra-Wideband Microwave Radiometer is a novel pseudo-correlation radiometer design measuring scene brightness temperatures from 0.5–2 GHz created under NASA's Instrument Incubator Program. This document analyzes the design and operation of the radiometer, the accuracy and stability of the brightness temperatures it produces, and presents initial results from a field campaign conducted in Greenland...
In this paper, using the Broadband Green's function with low wavenumber extraction (BBGFL) method, we develop the broadband Green's function for an arbitrary-shaped waveguide with two different dielectrics inside. We use the modes of an arbitrary-shaped waveguide to compute the broadband response of an arbitrary-shaped waveguide using the BBGFL method. In addition, we further apply the higher order...
Recent L-band radiometry from the SMOS and Aquarius satellite missions has sparked interest in studying low-frequency microwave-emission from the polar ice sheets [1, 2]. Low frequency microwaves have less extinction and extremely long penetration depth sin glacier ice (several hundreds to one thousand meters), and thus can provide sensitivity to the subsurface temperature profile. The Ultra-Wide...
Recently, we have developed the method of broadband Green's function with low wavenumber extraction (BBGFL) to investigate the problem of arbitrary shaped waveguides [1]. In the past, the Boundary Integral-the Resonant Mode Expansion (BIRME) [2, 3] method was applied to calculate the modes of an arbitrary shaped waveguide with a homogenous dielectric. In BIRME, a DC extraction is applied to remove...
The goal of the NASA SMAP L-band Active and Passive mission is to retrieve soil moisture with 4% accuracy for vegetated surfaces that have vegetation water content (VWC) less than 5 kg/m2. The satellite was launched in January 2015. After the failure of the radar on July 7, 2015, there has been increasing interest in using the Sentinel C-band radar data for the active part of the mission. In using...
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...
A novel approach of broadband Green's function with low wavenumber extraction (BBGFL)has recently been developed to calculate the band diagrams of two dimensional (2D) periodic structures using surface integral equations [1–3]. The surface integral equation takes the periodic Green's function as the propagator, provides the exact multiple scattering solution to the problem. A low wavenumber component...
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...
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