Showing papers on "Reflector (antenna) published in 2000"

Microwave ablation instrument with a directional radiation pattern

Abstract: A medical instrument is disclosed The medical instrument includes a transmission line suitable for the transmission of electromagnetic energy and an antenna coupled to the transmission line The antenna is configured for generating an electromagnetic field sufficiently strong to cause tissue ablation The medical instrument further includes a reflector arranged to be electrically coupled to the transmission line The reflector is positioned laterally to a first side of the antenna and configured for redirecting a portion of the electromagnetic field to a second side of the antenna opposite the reflector, wherein a majority of the electromagnetic field is directed away from the second side of the antenna

Reflector antenna and method of producing a sub-reflector

Abstract: A reflector antenna is disclosed with a main reflector and a rotatable sub-reflector that significantly reduces vibrations in the sub-reflector. The sub-reflector includes a reflecting surface located in front of the main reflector between the main reflector and a radiation source as well as a cylindrical shaft that extends in a direction parallel to a main axis of the main reflector. The sub-reflector is made of two connected parts, wherein one part includes the reflecting surface, and the other part is made of a non-reflecting material and formfittingly engages with the reflecting surface. The sub-reflector is rotatably supported on the cylindrical shaft and has a rotation speed of between approximately 1500 to 3500 rpm.

Methods for noninvasive analyte sensing

Abstract: Methods for measuring analyte concentration within a tissue using optical coherence tomography (OCT). Radiation is generated, and a first portion of the radiation is directed to the tissue to generate backscattered radiation. A second portion of the radiation is directed to a reflector to generate reference radiation. The backscattered radiation and the reference radiation is detected to produce an interference signal. The analyte concentration is calculated using the interference signal.

Artificial dielectric lens antenna

Abstract: An antenna device comprised of dielectric elements, the device having an array of parasitic director elements which coherently focuses energy across the parasitic array. The parasitic elements are spaced less than or equal to one wavelength from each other to provide the coherent focusing, with the array thereby acting like an artificial dielectric lens. An optimal spacing or elemental length might include one-eighth (⅛) to one-quarter (¼) wavelength. A plurality of feed elements is associated with the array and provides incident energy thereon. Reflector elements might also be used to further reflect incident energy from a feed element back across the parasitic array. The various elements are switchably selectable via a switching network which might consist of diodes. The parasitic elements form a lens which provides the directionality of the antenna. The switching network, and associated antenna control, provides the ability to dynamically alter the directionality of the antenna without moving parts. A tuning circuit can be associated with each element, with the tuning circuit being used to make certain elements appear electrically longer. The elements will generally be manufactured to be the same. If the tuning circuit grounds a particular element, then it will function as a director element, and can add to the overall gain of the device. If the tuning circuit makes an element electrically longer, then the element will function as a reflector. This device is useful in various applications, including fixed wireless subscriber terminals, base station to remote platform transmissions, radar tracking, and moving platform transmissions.

The rapid monitoring of structures using interdigital Lamb wave transducers

Abstract: The use of interdigital PVDF transducers for the quick inspection of large, plate-like structures is discussed. The transducers are designed to excite a particular Lamb mode in the structure, the region of the structure that is insonified being controlled by the transducer design. An example is given of the monitoring of an aluminium plate by a single, circular transducer operating in pulse-echo mode, the a0 Lamb mode at a frequency of about 1 MHz being transmitted and received. The transducer is split into segments so that the angular location of a reflector can be defined, the radial location of the reflector being determined from the time of arrival of the echo.

Combined optical sensor and communication antenna system

Abstract: The invention provides a combined optical sensor and communications antenna system (10). The system includes a primary reflector (12) for reflecting radiation. The primary reflector includes a centrally located core (14), which is adapted to transmit the radiation therethrough. An axis (18) centrally extending through the core forms an optical axis of the system. The system further includes a secondary reflector (16) positioned along the optical axis of the system for rereflecting and focusing the radiation reflected from the primary reflector toward the core of the primary reflector. The system still further includes a beam splitter (20) positioned adjacent the primary reflector on the opposite side from the secondary reflector, for separating and redirecting the radiation rereflected from the secondary reflector into an optical radiation component and a radiofrequency radiation component. Finally, the system includes a focal plane assembly (22) located adjacent the beam splitter to receive the optical radiation from the beam splitter, and a radiofrequency feed assembly (24) located adjacent the beam splitter to receive the radiofrequency radiation from the beam splitter.

Multiple pattern antenna having frequency selection zone or polarized wave sensing zone

Abstract: PROBLEM TO BE SOLVED: To provide a multiple pattern antenna where a plurality of antenna patterns with different frequencies or different polarization can be obtained from a single reflector. SOLUTION: A reflector antenna 10 is provided with a reflector 18 and a radiation source 20, and the radiation source emits a plurality of RF signals with pre-selected frequencies or polarization to the reflector. The reflecting body has a plurality of zones 22-26, and each zone reflects a pre-selected RF signal. The reflecting body generates a plurality of antenna patterns from the reflected RF signals. A pre-selected shape and size is formed to each zone so that the antenna patterns have a desired shape and beam width characteristic.

Deployable phased array of reflectors and method of operation

Abstract: A deployable phased-array-of-reflectors antenna includes individual reflectors and feed arrays. Each feed array is disposed above a corresponding individual reflector. The individual reflector antennas are preferably disposed adjacent to one another (e.g., on a hexagonal lattice) to form a phased array antenna using the individual reflectors antennas as elements. Phase and amplitude control electronics are coupled to each reflector antenna to provide steering for the signal energy coupled between the reflectors and the feed arrays. Switching electronics are coupled to the feed arrays and selectively activate and deactivate beam forming clusters of feeds in the feed arrays. A method for generating a steerable antenna pattern couples signal energy through a beamforming section to form steered signal energy. Next, the method couples the steered signal energy between a phased array of reflector antennas. The method selectively activates a first feed cluster for a first reflector, a second feed cluster for a second reflector, and so on, until feed clusters are activated in all of the reflectors in the array. The method then couples the steered signal energy between the first and second feed clusters. The method subsequently activates and deactivates the feed clusters to reduce the impact of grating lobes in the total antenna pattern, or when a particular cluster attenuation has been reached.

High flux led assembly

Abstract: A high intensity light source employs a plurality of light emitting diodes associated with a unitary reflector subassembly. The reflector subassembly defines an array of frustoconical reflectors arranged in rows and columns with the adjacent reflectors of each row being connected by a diverging slot with reflective wall surfaces. The light emitting diodes are mounted on a printed circuit board which forms a component of heat sink subassembly.

Solar cell array

Abstract: A solar cell array (10) where the reflector (25) has a first and a second reflecting side when the reflector (25) is in a deployed position. Preferably, the first and second reflecting sides of the reflector (25) are substantially symmetrically disposed about the longitudinal bisecting plane of the reflector (25) when the reflector (25) is in the deployed position. The reflector (25) is mounted so that the first side of the reflector (25) is adjacent to a row of solar cells (13), and the first reflecting side of the reflector (25) reflects radiation incident on the first side onto the adjacent row of solar cells (13) when the reflector (25) is in the deployed position.

Yagi antenna coupled with a low noise amplifier on the same printed circuit board

Abstract: A Yagi antenna system consisting of a low noise amplifier (LNA) and a reflector co-located on the same printed circuit board (PCB) as the radiators and directors is disclosed. Furthermore, the balun cable is replaced by surface mount devices whose feed line is implemented in microstrip technology, all co-located on the same printed circuit board.

Encapsulated packaging for thin-film resonators and thin-film resonator-based filters having a piezoelectric resonator between two acoustic reflectors

Abstract: An acoustic reflector ( 48 ) is applied over a thin-film piezoelectric resonator ( 41, 61 ) which is supported on a semiconductor or semiconductor-compatible substrate ( 42, 62 ) of a microelectronic device ( 40, 60 ), enabling an encapsulant ( 49 ) to be applied over the reflector-covered resonator without acoustically damping the resonator. In one embodiment, alternating high and low acoustic impedance layers ( 51, 53 . . . 55 ) of one-quarter wavelength thicknesses constructively reflect the resonating wavelength to make an encapsulant in the form of an inexpensive plastic molding compound appear as a “clamping” surface to a resonator ( 41 ) peripherally supported over an opening ( 43 ) on a silicon substrate ( 42 ). In another embodiment, an encapsulant- and reflector-covered resonator ( 61 ) is mechanically supported above a second reflector ( 68 ) which eliminates the need for peripheral support, making substrate ( 68 ) also appear as a clamping surface. The invention enables low cost plastic packaging of resonators and associated circuitry on a single monolithic structure. A radio frequency transceiver front-end application is given as an exemplary implementation.

Determination of Water Level and Tides Using Interferometric Observations of GPS Signals

Abstract: A nonintrusive remote sensing method to measure water level is examined. It relies on the fact that water is a good reflector of radio frequency energy, thus, on a satellite-to-ground path when the satellite is near the horizon, a readily detectable interference pattern is formed as the satellite moves through its orbit. Provided that the elevation angles from the ground-based receiver to the satellite are small enough for good reflection but not so small that atmospheric refractive effects contribute, the shape of this interference pattern is strongly related to the geometry of propagation. Results from interferometric observations of Global Positioning System (GPS) satellite signals are presented for two sets of measurements where the receiving antenna varied from 7 to 10 m above the nominal water surface. These results, compared to in situ or nearby tide gauges, show that water level is measured to an accuracy of about 12 cm. A GPS receiver, a laptop computer, and a clear over-water path to th...

Systems and methods for testing and calibrating a focused ultrasound transducer array

Abstract: Systems and methods for testing the performance of a focused ultrasound transducer array include transmitting ultrasonic energy from the transducer array towards an acoustic reflector, such as a planar air mirror, and receiving ultrasonic energy reflected off of the acoustic reflector using a sensing element. A characteristic of the reflected ultrasonic energy, such as amplitude and phase, is measured by processing circuitry, for example, by comparing the characteristic of the received ultrasonic energy to a corresponding characteristic of the transmitted ultrasonic energy to obtain an actual gain and phase shift for the received ultrasonic energy. A controller compares the actual gain and phase shift of the received ultrasonic energy to an expected gain and phase shift of the received ultrasonic energy. This information is used to calibrate the transducer array and/or to declare a system failure if the comparison indicates an error.

Diversity antenna system for lan communication system

Abstract: A diversity antenna structure for a wireless communication device for receiving and transmitting communication signals is provided. The antenna structure including a dielectric substrate defining a pair of major surfaces and having a conductive reflector element disposed upon one of the major surfaces of the dielectric substrate, said reflector element being operatively coupled to a pair of shield conductors of coax feedlines. The antenna further including a plurality of serpentine radiator elements conductively coupled to the reflector element. The antenna assembly also including a pair of transmission lines disposed upon the other major surface of the dielectric substrate substantially opposite the reflector element, each of the pair of transmission lines coupled to one of the center conductors of the coax feedlines, and a pair of conductive balun structures disposed upon the dielectric substrate and coupled to the pair of transmission lines, the baluns being disposed substantially opposite the plurality of serpentine radiators.

Retro-reflective scan module for electro-optical readers

Abstract: A miniaturized electro-optical, retro-reflective scanning module. The module has a base, a first circuit board, and a second circuit board mounted substantially orthogonal to the first circuit board. The base supports a light emitter for producing a scanning beam and optical elements for directing and collecting light energy. The emitted beam reflects off a fold mirror onto a reflector mounted on a drive for oscillation. The oscillating reflector, in turn, redirects the beam onto an indicia being read. The reflected light is reflected off the oscillating reflector and directed to the collection mirror before reaching a detector. The detector included in the module senses light reflected from an indicia scanned by the beam. The reflector is driven by an electro-magnetiz driven system, including a flexure and an actuation arm.

Yagi antenna having matching coaxial cable and driven element impedances

Abstract: A printed Yagi antenna of the present invention has a circuit board, a driven element having an impedance Ωd and being printed on the circuit board, a director element printed on the circuit board, a reflector element printed on the circuit board, a microstrip transmission line, and a coaxial cable having and impedance Ωc. The coaxial cable feeds the driven element via the miscrostrip transmission line and Ωc is approximately equal to Ωd. Further, the spacing between the reflector element, the driven element, and director elements are chosen so that an optimum balance is achieved between directional gain and performance sensitivity. The printed Yagi antenna has a partial folded driven element having a J shape which is grounded at the mid-point of the longest portion of the element. The configuration allows for a coaxial cable to be attached directly to the microstrip transmission line without the use of a matching network or balun.

Recessed lighting fixture

Abstract: A recessed lighting fixture includes a frame having an aperture and at least one mount and a reflector including at least one torsion spring configured to be received in the mount when the reflector is mounted to the frame A recessed lighting fixture also includes a frame and a reflector The frame includes an aperture and a pair of mounts separated around a circumference of the aperture in a first direction that differs from a distance in a second direction (ie, by an angle of other than 180°) The reflector includes a pair of torsion springs separated around a circumference of the reflector in the same way The reflector is designed to be received in the mount when the reflector is mounted to the frame The aperture may be a noncircular opening A junction box that can be used with a recessed lighting fixture includes a retaining spring and a plate having at least one edge having a slot cut into the edge The retaining spring is mounted on the plate and includes a retaining portion and an outer edge The retaining portion extends into the slot and the outer edge is substantially flush with the edge of the plate

Optically integrating pixel microstructure

Abstract: An integrated optical microstructure includes a substrate (245) carrying an optical waveguide (240) and supporting a medium (210) disposed to receive optical energy from the waveguide. The medium includes an optical re-radiator such as a phosphor (225), which re-radiates optical energy in response to optical energy received from the waveguide. The structure further includes a reflector (250, 255, 260) disposed to redirect some of the input optical energy emanating from the medium back into the medium, to achieve spatial confinement of the input light delivered by the input waveguide. The structure can thereby increase the efficiency of the light conversion processes of re-radiating materials. An aperture (235) in the reflector permits optical energy emitted by the re-radiator to emerge from the structure and to propagate in a preferred direction, such as toward a viewer or sensor. The structure is useful for increasing the brightness of various kinds of small emissive elements which are excited by light delivered from an integrated optical waveguide, including pixels in an information display.

Rear surface projection type display device

Abstract: A rear projection type display device capable of reducing the depth of a display device itself, comprising an optical engine (2), first, second, and third reflectors (3, 4, 5) disposed at such positions as to be easily held integrally with each other, a fourth reflector (6), a plane reflecting mirror (7) for turn-back of light flux, and a screen (8).

Wall switch and lamp assembly

Abstract: A wall switch and lamp assembly is constructed to include a lamp circuit and reflector unit covered on the wall. A wall switch unit is fastened to the wall to hold down the lamp circuit and reflector unit, and an intermediate light-penetrable panel is retained between the lamp circuit and reflector unit and the wall switch unit. The intermediate light-penetrable panel having a center opening, which receives the shell of the push-button switch of the wall switch unit. The lamp circuit and reflector unit include a circuit board having a set of LEDs. A light guide panel is adapted to receive the circuit board and to reflect the light of the LEDs through the intermediate light-penetrable panel.

Method and device for determining spatial positions and orientations

Abstract: The position of an object is determined by means of a laser-tracker (1) with an interferometer and a retroreflector (3) in the form of a triple prism or a triple mirror for parallel reflection of the laser beam (5) directed so as to impinge upon said reflector (3), on the basis of measurement data relating to the direction and optical path of said laser beam (5). Additional data relating to the angle of incidence (α) of said laser beam (5) in the reflector (3) and/or to a variable orientation of the reflector (3) in relation to the object (2) is determined on the basis of measurement data relating to the direction and optical path of the laser beam (5) and of said additional data. The additional data is also used to correct data derived from the direction measurement and the interferometric measurement concerning the angle of incidence (α) through cancellation of the dependence on said angle of incidence. To allow the measurement of the angle of incidence (α), the reflector (3) is designed so that a central part of the laser beam (5) penetrates said reflector (3) without being reflected and reaches a position sensor (12) placed in a fixed position behind the reflector (3) while a peripheral part of the laser beam (5) is reflected in a parallel manner and is used for the interferometric measurement.

Collapsible impulse radiating antenna

Abstract: A broadband collapsible impulse radiating antenna having a reflector 36 and feed arms 24 made from a flexible conductive material. An umbrella-like support mechanism is used to collapse and deploy reflector 36. The umbrella-like mechanism consists of a plurality of support ribs 52, a center support rod 22, center push rods 28, feed arm support rods 26, and push sleeve 32. Support ribs 52 are attached to the reflector 36 and are pivotally connected to a central hub 66. Push sleeve 32 slides along center support rod 22 causing the radial center push rods 28 to provide a radial force to reflector 36 and thereby deploy and collapse the antenna. Center can 12 contains center support rod 22 and an RF splitter 86 that splits the input signal into two feed cables of equal length leading to the feed point 54. Optional expandable seams can be provided in the reflector and feed arms so that the surface curvature of the reflector can be adjusted.

Headlamp for vehicle

Abstract: The present invention is to provide the headlamp for the vehicle characterized with the revolution paraboloidal reflector, the lamp in which the filament is located at a near focus of the reflector, the first reflecting plates to reflect the beam of more than about half of the beam from the above reflector to the oblique- upper and lower directions in the right and left sides or to the either direction respectively, the second reflecting plates arranged in parallel to the first reflecting plates to reflect the beam from the corresponding reflection faces in parallel to the same direction of the remained parallel beam, the slender rectangular shape front lens provided in front of the above reflector recieving the direct-parallel beam from the above reflector and the parallel beam from the second reflecting plates.

Bigrating light valve

Abstract: A spatial light modulator pixel comprises a movable reflective surface in which an array of subapertures is formed, wherein each subaperture contains a fixed (non-movable) island reflector. The movable reflector is micromechanically actuated so that the combination of movable and fixed reflectors functions alternately as a plane mirror or as a two-dimensional diffraction grating (i.e., a “bigrating”), depending on the movable reflector's position. The device is useful for applications such as maskless lithography and high-resolution printing.

Optical device and projection display

Abstract: An optical device which is suitable for use in a projection display comprises a spatial light modulator, such as a liquid crystal device, with a microlens array disposed on its front surface The microlenses are of convergent type, such as lenticules The spatial light modulator is of the reflective type and comprises a plurality of rear reflectors, each of which has convergent optical power in at least one direction The reflectors are arranged such that, for a given direction of illumination, each reflector forms an image of the aperture A of a microlens on the aperture B of another microlens or at a different position on the same microlens When used in, for example, a projection display, light losses caused by vignetting are reduced

Directed reflectors and systems utilizing same

Abstract: A wide angle directed reflector is disclosed. The directed reflector includes a lenticular layer (32) including al least one array of lenslets (34), each of which having a focal length. The directed reflector further includes a reflective layer (36) which is disposed relative to the lenticular layer. The lenticular layer and the reflective layer are constructed, designed and relatively such that light incident al an angle of incidence on the lenticular layer is reflected by the reflective laser and redirected through the lenticular layer at a substantially constant angle relative to the angle of incidence.