Engineering topics

Dominek, A. K.

Publications and source records attributed to Dominek, A. K..

9 records

NASA NTRS1995

A Numerical Analysis of Electromagnetic Scattering from Two-Dimensional Edge Terminations

Several techniques that influence the low frequency scattering from penetrable edge terminations are evaluated using a hybrid finite element and boundary element method code. The edge terminations consist of a dielectric skin forming an exterior shape with an internal conducting bulkhead. Some of the techniques considered are bulkhead shaping, internal material loading, placement of resistive cards, and the placement of lossy dielectric material rods. The intent of the various treatments is to find a combination or combinations that influence(s) the backscattered field to acceptable levels over a range of frequencies for both transverse magnetic and transverse electric polarizations.

Gray, B. E.↗

NASA NTRS1990

Constitutive parameter de-embedding using inhomogeneously-filled rectangular waveguides with longitudinal section modes

Constitutive parameter extraction from S parameter data using a rectangular waveguide whose cross section is partially filled with a material sample as opposed to being completely filled was examined. One reason for studying a partially filled geometry is to analyze the effect of air gaps between the sample and fixture for the extraction of constitutive parameters. Air gaps can occur in high temperature parameter measurements when the sample was prepared at room temperature. Single port and two port measurement approaches to parameter extraction are also discussed.

Park, A.↗

NASA NTRS1989

Radar cross section studies/compact range research

Achievements in advancing the state-of-the-art in the measurement, control, and analysis of electromagnetic scattering from general aerodynamic targets are summarized. The major topics associated with this study include: (1) electromagnetic scattering analysis; (2) indoor scattering measurement systems; (3) RCS control; (4) waveform processing techniques; (5) material scattering and design studies; (6) design and evaluation of standard targets; and (7) antenna studies. Progress in each of these areas is reported and related publications are listed.

Burnside, W. D.↗

NASA NTRS1988

Radar Cross Section Studies/Compact Range Research

A summary is given of the achievements of NASA Grant NsG-1613 by Ohio State University from May 1, 1987 to April 30, 1988. The major topics covered are as follows: (1) electromagnetic scattering analysis; (2) indoor scattering measurement systems; (3) RCS control; (4) waveform processing techniques; (5) material scattering and design studies; (6) design and evaluation of design studies; and (7) antenna studies. Major progress has been made in each of these areas as verified by the numerous publications produced.

Burnside, W. D.↗

NASA NTRS1987

Backscatter from a periodic rough surface at near grazing incidence

The effect of periodic surface roughness on the radar cross section (RCS) was studied. The surface roughness was formed by a small sinusoidal variation in a planar surface. RCS measurements were obtained for two different sinusoidal variations near grazing incidence for both principle polarizations. Significant grating lobes were observed in the measurements which directly correspond to the roughness characteristics. A physical optics solution was generated and compared to the measurements with reasonable agreement.

Dominek, A. K.↗

NASA NTRS1987

Design and implementation of the ESL compact range underhung bridge crane

As the indoor compact range technology has continued to increase, the need to handle larger and heavier targets has also increased. This need for target lifting and handling prompted the feasibility study of the use of an underhung bridge crane to be installed in the ESL (ElectroScience Laboratory, Ohio State University) compact range. This report documents both the design of the underhung bridge crane that was installed and the implementation of the design in the actual installation of the crane.

Shamansky, H. T.↗

NASA NTRS1987

Radar cross section studies

The ultimate goal is to generate experimental techniques and computer codes of rather general capability that would enable the aerospace industry to evaluate the scattering properties of aerodynamic shapes. Another goal involves developing an understanding of scattering mechanisms so that modification of the vehicular structure could be introduced within constraints set by aerodynamics. The development of indoor scattering measurement systems with special attention given to the compact range is another goal. There has been considerable progress in advancing state-of-the-art scattering measurements and control and analysis of the electromagnetic scattering from general targets.

Burnside, W. D.↗

NASA NTRS1986

Simulation of an aircraft flying through a ground station to satellite link

The effect of an aircraft which flies through a ground station-to-satellite link is determined. There are two aspects to the work reported here: (1) an aperture blockage theoretical solution developed by Rudduck and Lee was used to calculate the effect of a large aircraft (C5) for various satellite ground station antenna diameters, and (2) the compact range facility at the Ohio State University was used to measure various targets, including a 737 aircraft, and to validate the theoretical solution in item 1.

Rudduck, R. C.↗

NASA NTRS1986

Theory for computing the field scattered from a smooth inflected surface

A theory is described for computing the reflected or scattered field from a smooth body with inflection points. These inflections occur in certain directions at each surface point for which the total (Gaussian) curvature is zero or negative. For surface illumination in one of these critical directions, the usual reflection formulas obtained by the high-frequency approximation are inapplicable, and a shadow zone exists in the reflected field. Scattering into the shadow zone is treated, as well as specular reflection. This theory should have a variety of applications such as for certain optics problems, computer graphics modeling of three-dimensional shapes, and the design and analysis of specialized microwave reflector antennas.

Barger, R. L.↗