Impulse irradiation of layered medium by the open end of circular waveguide
The radiation of impulse signal from the open end of a circular waveguide is considered by analytical and direct numerical methods. The radiation of short pulse from the aperture is considered by calculation of special time form of field by means of modal basis method that permits to transform the nonstationary three-dimensional electrodynamic problem into the problem for one-dimensional evolutionary equations by means of the construction of modal basis for electromagnetic field with arbitrary time dependence. The method is applied to solve the problem of pulse evolution for positive and negative time with the use of Laplace transform by construction of operator of propagation. The approach is employed to form the short pulse on aperture of circular waveguide for irradiation of layered medium with losses.
Transient radiation from the open end of circular waveguide
The transient radiation from the open end of a circular waveguide is considered by simple analytical and direct numerical methods. The radiation of short pulse from the aperture is provided by calculation of special time form of field by means of modal basis method that permits to solve the problem of pulse evolution for positive and negative time with the use of Laplace transform. The radiation of the short pulse is calculated in Kirchhoff approximation and simulated by FDTD method. The frequency characteristics of the radiated field are considered.
L-band 3D imaging of an Alpine Glacier: Results from the AlpTomoSAR campaign
In this paper we present results from the tomographic analysis of L-Band SAR data acquired in February/March 2014 over the Mittelbergferner glacier, Austrian Alps, during the ESA campaign AlpTomoSAR. The campaign includes coincident in-situ measurements of snow and ice properties, as well as high-frequency Ground Penetrating Radar (GPR) data acquired over a total length of 18 km. The analyses of three-dimensional TomoSAR data cubes shows the complexity of the glacier sub-surface scattering. Most areas are characterized by surface scattering in proximity of the Lidar surface, plus a complex pattern of in-depth volumetric scattering beneath. Various subsurface features observed in GPR transects at 600 MHz and 200 MHz clearly showed up in TomoSAR sections as well. In particular: firn bodies, crevasses, and even the bedrock down to 50 m below the ice surface.