Showing papers on "Parabolic reflector published in 2006"

Satellite ground station antenna with wide field of view and nulling pattern using surface waveguide antennas

Abstract: The present invention is applicable to satellite ground station antennas having a wide field of view in comparison to the satellites with which the antenna connects One embodiment includes a parabolic reflector having a size that corresponds to a beam with an angular half-width larger than the spacing between neighboring interfering satellites It also has a feed comprising at least two dielectric rod-based surface waveguides coupled to the parabolic reflector configured to have a high sensitivity for a target satellite within the angular half-width of the reflector beam and a low sensitivity for neighboring interfering satellites within the angular half-width of the reflector beam

Illuminators using reflective optics with recycling and color mixing

Abstract: Various optical techniques are described for obtaining a specified light output from an LED source. One technique uses a parabolic reflector surrounding an LED or LED array to create a collimated beam, and the light exit opening of the parabolic reflector is defined by a reflective disc with an opening of the desired size. Any generated light that is outside of the opening is reflected back into the parabolic reflector and re-reflected until the light exits the opening. For mixing different light colors from different LEDs or energized phosphors, a mixing tunnel is used. The mixing tunnel includes angled dichroic mirrors or angled polarizer mirrors that selectively reflect and pass selected colors or polarizations of light to a single output port of the mixing tunnel. Efficient and compact ways to energize phosphors are also described. Other optical techniques are also described.

Reflective illumination device

Abstract: A reflective illumination device is disclosed, which is comprised of a light-guiding screen with light reflecting ability and at least a directional light source; wherein the light-guiding screen includes a reflecting surface having a semi-Fresnel lens structure arranged thereon. The semi-Fresnel lens structure, being designed basing on the principle of Fresnel lens, is the equivalent of a parabolic mirror that has spiral cut ridges for focusing light to a focal point, whereas the profile of the ridges can be a planar surface, a curved surface or the combination thereof. By arranging the reflecting surface with semi-Fresnel lens structure at the bottom of the light-guiding screen and each light source at a circumferential side wall of the light-guiding screen, the light beams emitting from each light source can be reflected out of the light-guiding screen by a specific angle as the direction of the light beams is adjusted to pour on the semi-Fresnel lens structure by a specific angle matching the configuration of the same.

Progress in 1m-class lightweight CFRP composite mirrors for the ULTRA Telescope

Abstract: Presented are results of continuing optical mirror development program for the NSF ULTRA Telescope. Development of a 16-inch f/4.0 parabolic mirror has been undertaken to adequately define scale-up fabrication procedures for 1m and 1.4m mirrors. 16-inch mirrors have been produced to λ/15 rms ( λ=633nm) in the wavefront. These mirrors have been used to produce astronomical images in a Newtonian telescope and yielded quality optical images. Presented will be results of the fabrication of the 1m, f/3 parabolic primary mirror mandrel for the 1m ULTRA Telescope. Also presented will be lab test data and astronomical mages produced under the 16-inch program as well as test data from the replications from the f/3 1m parabola.

Detection system operating at up to 7THz using quasioptics and Schottky barrier diodes

Abstract: We have developed a wide-bandwidth, high-sensitivity, continual terahertz-wave sensor that utilizes a quasioptical parabolic mirror and a Schottky barrier diode and successfully applied it at up to 7THz range. This sensor utilizes a parabolic cylindrical mirror, a long-wire antenna, and a Schottky barrier diode. The antenna, placed at the focal point of the parabolic mirror, quasioptically collects the terahertz signal. This configuration eliminates the need for frequency-dependent reception readjustments of the antenna and the mirror positions, greatly improving operability.

Parabolic antenna with rinsing connection

Abstract: Contamination at the exciter of a parabolic antenna can lead to impaired signal quality, or even system downtime. According to a sample embodiment of the present invention a parabolic antenna is provided, which in addition to a parabolic reflector and an exciter has a rinsing device, which is configured so as to rinse and clean the exciter with rinsing agent or protect it from contaminants. Herein, the rinsing agent is injected, dropped, or else blown from a rinsing outlet in an outlet member at the parabolic reflector onto the exciter. Mounting the rinsing outlet directly to the parabolic reflector allows for the exciter to be cleaned from the parabolic reflector.

Parabolic solar trough systems with rotary tracking means

Abstract: The inventive solar trough field system (A) comprises multiple parabolic reflectors ( 1 ), support circles ( 3 ) of which the center coincides with the focus of the parabolic reflector ( 1 ) and which are used in order to support the reflector ( 1 ), core mechanisms ( 2 ) which are located on the center of the circles ( 3 ), guy wires ( 4 ) which connect the circle ( 3 ) and the core mechanism ( 2 ) to each other, side support units ( 5,5 J) which bear the support circles ( 3 ) from their outer surfaces, lightweight filling materials ( 6 ) which support the reflectors ( 1 ) from their lower parts, thermal receiver tubes ( 11 ) which pass through the center axis of the circles ( 3 ). The parabolic reflectors ( 1 ) are rotated around the center axis of the circles ( 3 ), which is the focus thereof, and directed towards the sun. Thus, the parallel beams coming from the sun are concentrated in the thermal receiver tubes ( 11 ) which are located in the focus of the reflectors ( 1 ).

On the characterization of a reflector impulse radiating antenna (IRA): full-wave analysis and measured results

Abstract: There is a growing demand for impulse radiating antennas (IRAs) to receive and transmit short pulses. The basic concepts of IRA are reviewed and the far-field pattern versus frequency of an ideal IRA is characterized based on the fundamental properties of IRA. It is shown that the transmitted pulse is ideally in the form of a time derivative of the input pulse. The physical optics simulation results show that the far-field characteristics of a parabolic reflector are very close to an ideal IRA if it is fed properly. The reflector IRA was constructed, analyzed and measured at UCLA. The near-field and far-field characteristics of the reflector IRA are studied using both the method of moments (MoM) full-wave simulations and the frequency domain measurements. In this paper, the radiation mechanism of the reflector IRA is studied using a detailed current distribution on the parabolic reflector and the feeding structure at different frequencies. Applying either the calculated current distribution on the reflector IRA or the measured near-field results, it is seen that the aperture field intensity of the parabolic reflector is not the same in the two principle planes and as a result the beam-widths in the two principle planes are different. The far-field patterns of the antenna are measured and the calculated far-field patterns support the measured results. The calculated current distribution results provide a guideline on how to properly change the feeding structure to achieve a more uniform aperture field and increase the antenna radiation efficiency

Optical cavity for a gas sensor

Abstract: The present invention relates to an optical cavity for a Ngas sensor and particularly, to on- Dispersive InfraRed gas sensor. The optical cavity according to the present invention comprises two oppositely arranged parabolic mirrors having common focus located on the common optical axis of the parabolic mirrors; and a plane mirror arranged along the optical axis between the vertex of each of the parabolic mirrors.

A Tri-mode Horn Feed for Gravitationally Balanced Back-to-Back Reflector Antennas

Abstract: The concept of tri-mode feeds was used to lower the cross-polarization level in far-field pattern of offset parabolic reflector antennas. First, the complex mode coefficients of a tri-mode horn are optimized by using particle swarm optimization (PSO) technique. Using optimized complex mode coefficients, the performance of the reflector is simulated to verify the effectiveness of the method. The horn is then designed to provide the calculated optimum mode coefficients. The performance of the reflector is then simulated when it is fed by the designed horn and the results are compared with PSO optimized horn case. In addition, a simulation was performed to evaluate the bandwidth in which the horn can lower the level of cross polarization for at least 10 dB. The acceptable level of cross polarization verifies the possibility of utilizing these gravitationally balanced back-to-back reflectors fed by matched feed horns for narrowband applications in future spaceborne antenna missions requiring spinning platforms

Analysis of aperture illumination and edge rolling effects for parabolic reflector antenna design

Abstract: The radiation from parabolic reflector antennas for different amplitude and phase aperture illumination patterns is treated and the minimizations of the edge diffraction effects by edge rolling techniques are investigated in an accurate manner. The analytical regularization method (ARM) is used to solve the problem of E-polarized wave diffraction by parabolic shaped perfectly electrical conductive (PEC) cylindrical reflector with finite thickness. The initial boundary value problem is reduced to the infinite algebraic system of the second kind, which is an equation that can in principal be solved with any predetermined accuracy by means of the truncation procedure. The parabolic reflector is illuminated by a fictive feeder antenna which produces the desired phase and amplitude field distributions over the antenna aperture. Some edge rolling structures are analyzed to suppress the side and back lobes and to improve the aperture efficiency. The ARM procedure is verified by the analytical solutions and the calculated field patterns are presented for typical antenna configurations.

Design of a thermal imaging diagnostic using 90-degree off-axis parabolic mirrors

Abstract: Thermal imaging is an important, though challenging, diagnostic for shockwave experiments. Shock-compressed materials undergo transient temperature changes that cannot be recorded with standard (greater than ms response time) infrared detectors. A further complication arises when optical elements near the experiment are destroyed. We have designed a thermal-imaging system for studying shock temperatures produced inside a gas gun at Sandia National Laboratories. Inexpensive, diamond-turned, parabolic mirrors relay an image of the shocked target to the exterior of the gas gun chamber through a sapphire vacuum port. The 3000-5000-nm portion of this image is directed to an infrared camera which acquires a snapshot of the target with a minimum exposure time of 150 ns. A special mask is inserted at the last intermediate image plane, to provide dynamic thermal background recording during the event. Other wavelength bands of this image are split into high-speed detectors operating at 900-1700 nm and at 1700-3000 nm, for time-resolved pyrometry measurements. This system incorporates 90-degree, off-axis parabolic mirrors, which can collect low f/# light over a broad spectral range, for high-speed imaging. Matched mirror pairs must be used so that aberrations cancel. To eliminate image plane tilt, proper tip-to-tip orientation of the parabolic mirrors is required. If one parabolic mirror is rotated 180 degrees about the optical axis connecting the pair of parabolic mirrors, the resulting image is tilted by 60 degrees. Different focal-length mirrors cannot be used to magnify the image without substantially sacrificing image quality. This paper analyzes performance and aberrations of this imaging diagnostic.

Compact multifunction sight

Abstract: A multifunction sight is disclosed. The multifunction sight includes an body, a receiving aperture, an emitting aperture, a parabolic reflector, and an optical detector. The receiving aperture passes radiation in a first band and a second band into the body where the first band is different from the second band. The emitting aperture that passes the radiation in the first band out of the body. The parabolic reflector displays a point source such that the point source is visible from the emitting aperture. The point source appears aligned with where the multifunction sight is aimed irrespective of a visual alignment with the emitting aperture. The optical detector is affixed to the body and coupled to the radiation in the second band, and receives coded radiation with the second band.

Focusing characteristics of a planar solid-immersion mirror

Abstract: The focusing characteristics of a planar waveguide solid-immersion mirror with parabolic design have been investigated. The solid-immersion mirror is integrated into an optical waveguide, and light focusing is achieved with a parabolic mirror parallel to the waveguide plane and waveguide mode confinement normal to the waveguide plane. Optical-quality tantala silica planar waveguides can be obtained by evaporation. The parabolic sidewall reflects over 50% of the incident waveguide mode and generates a diffraction-limited focus. The measured spot size for the solid-immersion mirror described here is less than one third of the wavelength. Polarization analysis shows that the electric field near the focal region has components parallel and normal to the polarization state of the incident beam. The planar solid-immersion mirror is essentially free of chromatic aberration, and the alignment of the illumination beam is within a fraction of degrees.

Front illuminating device for vehicle

Abstract: The lighting device positioned on front end of car includes a self-body; at least two lamp sockets placed on the self-body, every lamp socket includes a parabolic reflector, and a lens is set on the opening end of said parabolic reflector; at least two light-emitting diode components respectively set on the parabolic reflectors of these lamp sockets; and a starting component respectively electrically-connected with above-mentioned light-emitting diode components and respectively for controlling these light-emitting diode components

Parabolic aerial with a conical diffusion disc for fill level radar

Abstract: Reflections on the aerial system of a fill level radar result in reduced measuring quality at short range. Small echo signals at short range can thus disappear in the noise. According to one embodiment of the present invention a parabolic aerial for a fill level radar is stated, which parabolic aerial comprises a parabolic mirror, an exciter and a diffusion disc. The diffusion disc is used for laterally removing interfering electromagnetic waves that would otherwise be absorbed by the exciter. In this way the decay behaviour at short range can be reduced.

Waste incineration system using solar heat obtained by condensing sunlight

Abstract: PROBLEM TO BE SOLVED: To resolve a problem in incinerating "refuse" or the like by using solar heat wherein a temperature of an incineration part is affected by weather causing a large problem in an incineration condition of the incineration part, and consequently, there is a need to adjust incineration output in regard to the problem. SOLUTION: Since the temperature of the incineration part is affected by weather, and there is a need to deviate a heating part of a device from a focal point of a parabolic mirror to adjust the incineration output, when it is almost cloudy weather, sunlight is condensed on the focal point or near the focal point of the parabolic mirror, and when it is fine weather, it is alright to condense the sunlight at a position separated from the focal point on an optical axis of the parabolic mirror. To that end, the parabolic mirror is composed of segment mirrors, orientations of the segment mirrors are controlled so as to separate away from the focal point, and the heating part of the device using solar heat is controlled. COPYRIGHT: (C)2006,JPO&NCIPI

Miniature portable infrared spectrograph

Abstract: A minimized and portable infrared spectrograph is composed of pulse infrared ray source, parabolic reflector, scanning micro ?C lens, flash grating, steering reflector, slit and high sensitivity of room temperature infrared unit detector. It features that a new light path system and pulse infrared ray source based on MEMS technology are applied on said spectrograph.

Micromirror spectrometer for spectroscopic proof and regulation of biological, chemical agents in environmental monitoring, comprises radiation source, parabolic reflector, micromirror, diffraction gratings, detector and control device

Abstract: The reflector (16), micro mirror (18) and the grating (20) are placed, where the radiation emitted by the continuous light source (1-10 mu m) reflects a probation (14), which pass through or reflects from a probation. The radiation of the reflector is directed by reflection at the micromirror on the gratings. Bent radiation is directed by reflection at the mirror and at the reflector on the detector (24). The control device is connected with the detector and to the mirror to adjust the source of light and angle of rotation of the mirror is placed and accomplish extinction/reflection measurements. The continuous source of light is emitted by radiation source (10) and transmitted through sample. An optical probe is placed in the path of rays behind the light source to direct the radiation of the source on the sample and to receive and pass the reflected radiation from the sample. The device covers a durable housing, in which the radiation source, the reflector, the micro mirror, the optical probe, the detector and the control device are accommodated. Independent claims are also included for: (1) a method; and (2) a spectroscopic module comprising the above device.

Modeling and Design of Offset Parabolic Reflector Antennas using Physical Optics and Multilevel Fast Multipole Method Accelerated Method of Moments

Abstract: Modern radio, wireless and satellite communication and radar systems often involve electrically large and arbitrarily shaped metallic surfaces those span many wavelengths in three dimensions. High frequency asymptotic techniques e.g. current based physical optics (PO), ray based uniform theory of diffraction (UTD) represent approximate forms for solving radiation and scattering problems, and more accurate solutions are sometimes desired. Exact numerical results can be found by solving integral equations (IE's) using the method of moments (MoM). Application of the moment method to an integral equation yields full coupling matrices resulting in bad computational complexity and more importantly memory resources are fastly becoming insufficient for large objects. Recently a multilevel fast multipole method (MLFMM) accelerated MoM technique has been implemented for the efficient and yet accurate solution of radiation and scattering problems for arbitrarily shaped electrically large structures. The MLFMM-MOM scheme provides accurate solutions in the regions where asymptotic techniques do not produce good results. This approach is used for the numerical computation of radiated fields of offset parabolic reflector antennas. Excellent agreement of physical optics results in the main lobe and out to several lobes has been found with those of MLFMM accelerated MoM technique. Because of current singularities at edges of reflector and absence of feed coupling effects in physical optics formulations, significant deviations of PO results are observed in far side lobes. Review of the computational techniques is presented and numerical results for two reflector antennas are shown.

Vehicular head lamp

Abstract: PROBLEM TO BE SOLVED: To provide a vehicular head lamp capable of automatically changing travelling-beam light distribution pattern according to the travelling condition of a car, etc., and light in weight, compact and inexpensive. SOLUTION: The vehicular head lamp 10 includes: a low beam unit 18 irradiating a low beam light distribution pattern; and a main beam unit 20 irradiating a main beam light distribution pattern. The main beam unit 20 includes: a halogen bulb 28 provided with a sub filament 28a and a main filament 28b having a shade 28c arranged at a side thereof on the right side of the vehicle; and a parabolic reflector 30 having a first reflection surface 30a that is formed to cover half of the parabolic reflector on the right side of the vehicle and that at least reflects light from the sub filament 28a toward the front of the vehicle, and a second reflection surface 30b that is formed to cover half of the parabolic reflector on the left side of the vehicle and that reflects light from the main filament 28b toward the front of the vehicle. By controlling the turning on/off of the halogen bulb 28 and the low beam unit 18, light distribution pattern is selectively switched among a plurality of different patterns. COPYRIGHT: (C)2011,JPO&INPIT

Diffraction reflection of a focused X-ray wave by a multilayer crystal

Abstract: The Bragg diffraction of a narrow X-ray beam in a multilayer crystal is studied in the reflection geometry. It is shown by computer simulation of the experiment that strong integrated kinematic reflection occurs at any boundary of a multilayer crystal at the point of intersection of a narrow beam with the boundary. In contrast to the dynamic diffraction of a plane wave, attenuation of a narrow incident beam due to the reflection is small in comparison with the conventional absorption. As an example of a multilayer crystal, a Fabry-Perot interferometer is considered, which consists of two 70-μm-thick crystal Si layers separated by a 100-μm-thick air layer. The 12 4 0 reflection is studied at a photon energy of 15 keV. Three methods of formation of a narrow beam are considered: wavefront limitation by a slit, focusing with a parabolic lens, and focusing with a zone plate. It is shown that, for a local analysis of the thickness of layers and scattering parameters, the method of parabolic lens focusing has some advantages in comparison with the other methods.

Multiple reflection type cell, and infrared type gas detector

Abstract: PROBLEM TO BE SOLVED: To provide a multiple reflection type cell which is reduced in size while securing a long optical path length enough to be required, and manufactured easily without generating an individual difference and a lot difference, and also to provide an infrared type gas detector which is provided with the multiple reflection type cell, and detects expected gas surely. SOLUTION: This multiple reflection type cell is constituted to reflect multiply emission light from a light source so as to be get incident into a photodetector, and is arranged opposedly with two parabolic reflectors of focal distance lengths different from each other, under the condition where focal positions thereof are conformed to each other. This infrared type gas detector of the present invention is provided with the multiple reflection type cell. COPYRIGHT: (C)2007,JPO&INPIT

Insect extermination device has ultrasonic generator attached to parabolic reflector whereby telescopic bar is coupled to reflector and energy source or electric connection point supplies energy to ultrasonic generator

Abstract: The device has an ultrasonic generator or producer which is attached to the parabolic reflector. A telescopic bar is coupled to the reflector whereby a handgrip is attached at the end of the telescopic bar. An energy source or electric connection point supplies energy to the ultrasonic generator. A controller is provided which is coupled to the ultrasonic transmitter (1). An independent claim is also included for the mold or insect abatement device.

Imaging property of dual parabolic reflector and its application in lamp manufacture

Abstract: Dual paraboloidal reflectors (DPR) can couple more light into small etendue projection systems. The imaging property of DPRs at two conjugation focal points and their peripheral areas has been investigated using ASAP simulation and observation. The result confirms that the DPR can produce one to one image at the conjugated focal points, which is the reason why dual parabolic reflectors are beneficial. In the periphery area, the image is distorted. The image distortion was analyzed theoretically and the results agree with observation. This imaging property was used to develop a new method of locating the focal points of DPRs accurately. A new lamp manufacturing procedure and a pilot line were setup and tested. The coupled lumen efficiency has been increased by 13%.

Surface gradient integrated profiler for x-ray and EUV optics: 3D mapping of 1m-long flat mirror and off-axis parabolic mirror

Abstract: A new ultra-precision profiler has been developed in order to measure such as asymmetric and aspheric profiles. In the present study, the normal vectors at each points on the surface are determined by the reflected light beam goes back exactly on the same path as the incident beam. The surface gradients at each point are calculated from the normal vector and the surface profile is obtained by integrating the gradient. The measuring instrument was designed according to the above principle of the measuring method. In the design, four ultra-precision goniometers were applied to the adjustment of the light axis for the normal vector measurement. The angle positioning resolution and accuracy of each goniometer are respectively 0.018 μrad and 0.2 μrad. In the measuring instrument, the most important item is the measuring accuracy of the normal vectors by the goniometers. Therefore, the rotating angle positioning errors were measured and calibrated. Then the measurement of a concave mirror with 300 mm radius and 460mm, 1m long plane mirrors were measured. Then, The 3D surface profile of the mirror such 1m-long flat mirror, a concave mirror with 2000 mm radius and off-axis parabolic mirror are obtained by integrating the interpolated gradient.