Effect of an aperture on measurement of the axial distribution function in a magnetically confined plasma
Distortion in axial velocity distribution when magnetically confined plasma passes through aperture
Krawec, R.↗
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Precision pointing of large aperture, diffraction-limited, space telescopes
Minimum pointing error of large aperture space telescopes as function of diameter, servo bandwidth, and star brightness
Wischnia, H. F.↗
Aperture filtering and saturation of scintillation
Stellar scintillation saturation at large zenith angles interpreted in terms of combined dispersion and aperture filtering
Young, A. T.↗
Modal decomposition of aperture fields in detection and estimation of incoherent objects
Aperture field modal decomposition of optical system in terms of integral equation eigenfunctions during detection and estimation of incoherent objects
Helstrom, C. W.↗
Microwave properties of thin films with apertures
Microwave transmission through thin film screens with apertures placed in transverse plane of X band rectangular guides
Landes, H. S.↗
Enhancing efficiency of single, large-aperture antennas
Numerical analysis method provides means of describing energy distribution in focal plane of parabolic surface in terms of phase and wavelength. Two approaches for enhancing antenna efficiency include single, large reflector focused to feeding element, and array of smaller apertures whose individual outputs are summed.
Cohen, M.↗
Focussing system for an ion source having apertured electrodes Patent
Apertured electrode focusing system for ion sources with nonuniform plasma density
Sohl, G.↗
Arrays of large aperture antennas - An experimental evaluation
Experimental analysis of system requirements for arrays of large aperture antennas
Deerkoski, L. F.↗
Aperture configuration and imaging performance
Optical aperture configurations effect on image performance, discussing large telescope systems design criteria
Sheehan, P. J.↗
Optimization criterion for illuminating circular antenna apertures
Worst case criterion for finite circular antenna aperture illuminations effectiveness comparison and optimization in synthesizing ideal radiation pattern
Holland, R.↗
Annular objective apertures improve resolution of electron microscopes
Hollow-cone illumination techniques, using an annular objective aperture located behind back focal plane of objective lens, increase image contrast and minimize chromatic aberrations.
Heinemann, K.↗
An investigation of photosensor aperture shaping in facsimile cameras
Optical-mechanical scanning techniques are generally employed in instruments specifically designed to spectrally or radiometrically characterize variations in scene brightness. The effect of aliasing, which can be caused by line scan sampling, on the spatial detail of the reconstructed image has, therefore, been of little concern. Emphasis of some recent applications of optical-mechanical scanning techniques in facsimile cameras is, however, on the spatial characterization of the scene which, as is shown, can be severely degraded by aliasing. The characteristics of aliasing are analyzed to establish quantitative bounds, and photosensor aperture shaping and line scan spacing are investigated as a means for reducing this degradation.
Katzberg, S. J.↗
An analysis of the effect of aperture shapes in reducing facsimile camera aliasing.
Optical-mechanical scanning techniques are frequently employed in instruments specifically designed to spectrally or radiometrically characterize variations in scene brightness. The effect of line scan sampling on the spatial detail of the reconstructed images has, therefore, received little attention. Emphasis of some recent applications of optical-mechanical scanning techniques is, however, on the spatial characterization of the scene which, as is shown here, can be severely degraded by aliasing generated in common scanner designs. The characteristics of aliasing are analyzed to establish quantitative bounds, and photosensor aperture shaping and line scan spacing are investigated as a means for reducing this degradation.
Katzberg, S. J.↗
Diffraction by an aperture between two wedges.
An asymptotic solution for large spacing is obtained in the problem of diffraction by an aperture between two conducting wedges. The variation of the wedge angles is shown to have significant effect on the far field amplitude of the transmitted field in certain ranges of angle for E-polarization. The wedge angles are seen to have a greater effect than interaction corrections in some cases but a lesser effect in others. Numerical comparisons are carried out.
Teague, B. R.↗
Antenna dimensions of synthetic aperture radar systems on satellites
Design of a synthetic aperture radar (SAR) for a satellite must take into account the limitation in weight and dimensions of the antenna. The lower limits of the antenna area are derived from the conditions of unambiguity of the SAR system. This result is applied to estimate the antenna requirements for SARs on satellites in circular orbits of various altitudes around Earth and Venus.
Richter, K. R.↗
Processing for spaceborne synthetic aperture radar imagery
The data handling and processing in using synthetic aperture radar as a satellite-borne earth resources remote sensor is considered. The discussion covers the nature of the problem, the theory, both conventional and potential advanced processing techniques, and a complete computer simulation. It is shown that digital processing is a real possibility and suggests some future directions for research.
Lybanon, M.↗
Method and apparatus for sputtering utilizing an apertured electrode and a pulsed substrate bias
The method and equipment used for sputtering by use of an apertured electrode and a pulsed substrate bias are discussed. The technique combines the advantages of ion plating with the versatility of a radio frequency sputtered source. Electroplating is accomplished by passing a pulsed high voltage direct current to the article being plated during radio frequency sputtering.
Przybyszewski, J. S.↗
The use of a simulator in a synthetic aperture radar data processing tradeoff study.
A computer simulation of a synthetic aperture radar system is described. The objective in developing the simulator was to make it possible to assess the imaging performance of various configurations against a variety of target types. The simulation involves targets, the radar system itself, and the processor; several analysis and output options are provided. Targets may be internally generated or come from external sources, or externally produced (e.g., real) radar signals can be used. A number of parameters of the radar system can be varied. The characteristics of the processor can be adjusted to a considerable extent. Statistical analyses may be performed. Several output options are available, including imagery.
Lybanon, M.↗