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Reflector (antenna)

About: Reflector (antenna) is a research topic. Over the lifetime, 28730 publications have been published within this topic receiving 212618 citations.


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Patent
14 Apr 2004
TL;DR: In this paper, a communication device (10) and a corresponding method are arranged for changing the radiation pattern of an antenna (14), where the radiation patterns of the antenna are set to a half-space pattern if the communication device is in close proximity to an object.
Abstract: A communication device (10) and a corresponding method are arranged for changing the radiation pattern of an antenna (14), where the radiation pattern of the antenna (14) is set to a half-space pattern if the communication device (10) is in close proximity to an object. A reflector (18) is activated to produce the half space radiation pattern. The reflector (18) is deactivated to produce the full space pattern. A switching device (26) determines the state of the reflector (18). A sensing and control device (23) controls the state of the switching device (26).

74 citations

Journal ArticleDOI
TL;DR: In this article, a vertical external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a subwavelength array of antenna-coupled quantum-cascade subcavities.
Abstract: A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

74 citations

PatentDOI
TL;DR: In this paper, a kidney stone disintegrating system includes a computer-controlled aiming system with a reflector containing water through which the reflector is coupled to a living body having a kidney, and a pair of ultrasound transducers are carried by an articulated support comprising a plurality of pivotally interconnected arms.
Abstract: A kidney stone disintegrating system includes a computer-controlled aiming system. The disintegrating system includes a reflector containing water through which the reflector is coupled to a living body having a kidney stone. The reflector is a portion of an ellipsoid and a spark gap generator is located at one focus of the ellipsoid. An electrical energy source is connected to the spark gap generator for generating a spark which in turn generates a shock wave in the fluid. Three motors are connected to the reflector for moving it in respectively X-axis, Y-axis and Z-axis directions to locate the reflector so that the kidney stone lies at the second focus point thereof. A pair of ultrasound transducers are carried by an articulated support comprising a plurality of pivotally interconnected arms. Precision potentiometers are provided between the arms to indicate the relative positions thereof, and electrical potentials from the potentiometers are connected to a computer. The signals and the computer are connected to a monitor having a screen to display the kidney stone, and particularly the position thereof as determined by the two transducers. The computer is connected to the three motors to position the reflector in accordance with the positions of the transducers to locate the reflector with the second focus point coinciding with the kidney stone. Controls are provided for causing generation of a spark with the resulting shock wave focused on the kidney stone to destroy the kidney stone.

74 citations

Journal ArticleDOI
W.J. Tanski1
TL;DR: In this paper, the design of high-Q low-distortion surface acoustic wave (SAW) resonators requires techniques and data for minimizing acoustic losses and accurate placementof the device resonance.
Abstract: Abstruct-The design of highQ lowdistortion surface acoustic wave (SAW) resonators requires techniques and data for minimizing acoustic losses and accurate placementof the device resonance Several aspects of one- and two-port SAW resonator design and fabrication are discussed It is shown that devices on quartz consisting of recessed aluminum transducers and shallow reflecting groove arrays can be fabricated with very high Q values The properties of the shallowgrooved reflector are analyzed both experimentally and theoretically Experimental valuesof the surface wave velocities for reflectors, transducers, and the free surface are reported, and transducer placement and maximum cavity length are discussed It is shown that the maximum cavity length possible, without additional resonant modes, increases asthe goove depth decreases Cavity length corrections required to center a resonance in the reflector stopband are derived, and resonator fabrication for the recessed-transducer/shallowgrooved reflector configuration is discussed SAW devices with Q values of 75 000 (at 71 MHz) and resonators at frequencies above one GHz (with Q values over 3200) have been fabricated

74 citations

Patent
30 Jul 1999
TL;DR: In this article, a planar filament emission element was used for producing and detecting radiation having width dl/l less than about 0.1 to test a sample gas, where l is the wavelength of the radiation; a reflector ( 108 ); a window (W); an electrical control ( 118 ); and a data output element ( 116 ).
Abstract: A blackbody radiation device ( 110 ) includes a planar filament emission element ( 102 ) and a planar detector ( 104 ) for respectively producing and detecting radiation having width dl/l less than about 0.1 to test a sample gas, where l is the wavelength of the radiation; a reflector ( 108 ); a window (W); an electrical control ( 118 ); and a data output element ( 116 ).

74 citations


Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20224
2021567
2020948
20191,159
20181,092
2017977