Showing papers on "Parabolic reflector published in 1969"
TL;DR: In this paper, an analysis of the field structure and energy flow near the axis of any circularly symmetric focusing reflector is applied to the case of a spherical reflector and an estimate is made of the attainable efficiency of corrugated-waveguide aperture-type feeds.
Abstract: An earlier analysis of the field structure and energy flow near the axis of any circularly symmetric focusing reflector is applied to the case of a spherical reflector From the results an estimate is made of the attainable efficiency of corrugated-waveguide aperture-type feeds
23 citations
Patent•
23 Apr 1969
TL;DR: A portable handheld searchlight for providing a high-intensity beam of electromagnetic radiation for comparatively long periods of time from a self-contained, easily portable power source is described in this article.
Abstract: A portable handheld searchlight for providing a high-intensity beam of electromagnetic radiation for comparatively long periods of time from a self-contained, easily portable power source. A Xenon gas discharge lamp is utilized as the source of electromagnetic radiation in the searchlight and it is reflected therefrom by a conventional parabolic reflector. Mechanical adjustments are provided for moving the Xenon lamp along the axis of the parabolic reflector to points closer thereto and further therefrom than a focal point of the parabolic reflector to vary the dispersion or divergence of the reflected beam. A radial adjustment for positioning the Xenon lamp along the axis, which adjustment is generally only made once at the time of manufacture, may also be provided. A light shield comprising a cylindrical tubing around the Xenon lamp is also incorporated as part of the structure to intercept the electromagnetic radiation emitted from the lamp that has not been reflected from the reflector and allows transmission thereof only in directions substantially parallel to the axis of the reflector. A complete electrical power supply system including a battery for providing electrical energy, and circuitry for providing the functions of comparatively high voltage for starting or igniting the gas discharge lamp and intermediate parallels of electrical energy to the lamp after ignition but prior to steady state operation, and also electrical energy of a comparatively low voltage for sustained steady state operation.
16 citations
Patent•
12 Mar 1969
TL;DR: In this paper, the main lobe of an antenna with a large spherical reflector and a small reflector may be oriented with respect to the large reflector by virtue of the displacement of the small reflectors.
Abstract: An antenna having a large spherical reflector and a small reflector, wherein the main lobe may be oriented with respect to the large spherical reflector by virtue of the displacement of the small reflector, these displacements being rotations around the center of curvature of the large reflector, and the waves irradiating the small reflector being spherical around the same center, the beam formed by these waves shifting with the displacement of the small reflector.
9 citations
Patent•
10 Dec 1969
TL;DR: In this paper, a beam of coherent light is expanded and reparallelized by a single lens and a parabolic mirror at 45 degrees to create fringes in the overlapping reflected images which can be visually observed or recorded directly on film.
Abstract: A beam of coherent light is expanded and reparallelized by a single lens and a parabolic mirror. The beam then passes through the test region, which may be of any convenient size and impinges on a back surface mirror at 45 degrees. About 10 percent of the light is reflected from the front surface of the glass. This is slightly offset from the image reflected from the rear surface. Any refractive index gradients perpendicular to the direction of propagation then create fringes in the overlapping reflected images which may be visually observed or recorded directly on film.
8 citations
TL;DR: The principal component of the parabolic-reflector focal-plane electric field distribution is derived from scalar wave theory in a form providing a simple analytic representation of the field in terms of available tabulated functions not restricted to large focal-length/diameter ratios.
Abstract: The principal component of the parabolic-reflector focal-plane electric-field distribution is derived from scalar wave theory in a form providing a simple analytic representation of the field in terms of available tabulated functions not restricted to large focal-length/diameter ratios.
5 citations
Patent•
09 Sep 1969
TL;DR: In this paper, a parabolic reflector with a four-quadrant photodetector mounted at its focus is used for boresighting a telescope to a laser.
Abstract: A telescope having crosshairs is mounted on the housing of a laser. In order to boresight this telescope to the laser, a parabolic reflector with a four-quadrant photodetector mounted at its focus is provided. The detector has its quadrants defined by surface crosshairs, and is physically adjustable about the axis of the reflector. Microammeters are connected to show the current provided by each quadrant of the photodetector. In use, the reflector is placed in the beam of a laser, and the photodetector is physically adjusted until all microammeters show the same reading. The laser telescope is then adjusted to have its crosshairs align with the image of the crosshairs of the photodetector.
5 citations
Patent•
12 Jun 1969
TL;DR: In this paper, a frontal parabolic mirror with half opening theta 1 (angle made by a straight line connecting the focus and the mirror edge with reference to the optical axis) was used to capture the first concentration of a flux captured from a distant source of radiation, forming an image in the smallest section of a bundle of convergent rays.
Abstract: The present invention relates to an optical concentrator with maximum illumination, comprising a frontal parabolic mirror with half opening theta 1 (angle made by a straight line connecting the focus and the mirror edge with reference to the optical axis) effecting a first concentration of a flux captured from a distant source of radiation, forming an image in the smallest section of a bundle of convergent rays with half angle opening theta 1 with the optical axis, and a truncated cone mirror whose entrance section of diameter d1 is disposed to coincide with the so-called Gaussian image furnished by the said frontal parabolic mirror, and whose terminal section, of smaller diameter, is associated with a sensitive element or radiation transformer of a receiver.
4 citations
Patent•
15 Dec 1969
TL;DR: An antenna with a parabolic reflector including a wave absorber in the vicinity of the circumferential edge of the reflector as discussed by the authors is composed of layers of different absorbing materials.
Abstract: An antenna having a parabolic reflector including a wave absorber in the vicinity of the circumferential edge of the reflector. The absorber is composed of layers of different absorbing materials. The edge of the reflector is inserted into one of the layers. The absorber extends beyond the edge of the reflector, thereby providing an improved front-to-back ratio of wave transmission.
4 citations
TL;DR: The results of some ray tracing calculations are presented in graphical form for various single and double pass configurations of a large plane grating with parabolic collimators and aperture f/10.
Abstract: The results of some ray tracing calculations are presented in graphical form for various single and double pass configurations of a large plane grating with parabolic collimators and aperture f/10. Some advantages of systems with vertical displacement of slits above and below the grating are discussed. Results of calculations employing spherical mirrors are summarized briefly.
3 citations
Patent•
12 Jun 1969
TL;DR: In this paper, an optical concentrator without flux loss was proposed, comprising a parabolic frontal mirror with half opening 1 (angle made to the optical axis by a straight line that joins the focus to the mirror edge) effecting a primary concentration of a flux captured from a distance source of radiation.
Abstract: The present invention relates to an optical concentrator without flux loss, comprising a parabolic frontal mirror with half opening 1 (angle made to the optical axis by a straight line that joins the focus to the mirror edge) effecting a primary concentration of a flux captured from a distance source of radiation, forming a spot image in the smallest section of a beam of convergent rays with half angle opening theta 1 with the optical axis, and a truncated cone mirror whose entrance section of diameter d1 is disposed in coincidence with the total spot image furnished by the said frontal parabolic mirror and whose terminal section which is of smaller diameter is associated with a sensitive element or radiation transformer of a receiver.
2 citations
TL;DR: In this paper, the focal properties and spherical aberration of a simple model of a field omission electron gun were investigated theoretically, and the results were presented graphically for a fixed source position and a fixed image position.
Abstract: The focal properties and spherical aberration of a simple model of a field omission electron gun are investigated theoretically. Results are presented graphically. For a fixed source position, spherical aberration decreases as the grid aperture increases, but for a fixed image position, spherical aberration decreases as the grid aperture decreases, down to 0.1 S, where S is the grid-anode distance. The results are almost independent of the anode aperture.