Topic
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•
09 May 2007
TL;DR: In this article, a system and apparatus including a wireless network architecture that provides broadband data network coverage over an expandable geographic area is presented, including a high-frequency wireless modem enabling high data rate access to the wireless network in a spectrally efficient manner using SSB modulation.
Abstract: A system and apparatus including a wireless network architecture that provides broadband data network coverage over an expandable geographic area. A media access control layer is also provided that facilitates access to the broadband wireless network. A high-frequency wireless modem enables high data rate access to the wireless network in a spectrally-efficient manner using SSB modulation. A wideband millimeter-wave antenna includes a cosecant-squared reflector enabling signal propagation between network elements thereby enabling seamless wireless communications. A millimeter-wave polarizer, and a septum polarizer each convert between linear and circular polarization. A cross-shaped horn antenna adapted for circularly polarized signals can also be used in combination with the septum polarizer. A combined horn antenna is fed using a microstrip patch antenna.
262 citations
TL;DR: In this paper, the authors presented a derivation of the stationary phase principle of seismic interferometry for a homogeneous medium with one horizontal reflector and without a free surface, and showed that the correlation of the waves recorded at two receivers correctly gives both the direct wave and the singly reflected waves.
Abstract: Seismic interferometry is a technique for estimating the Green’s function that accounts for wave propagation between receivers by correlating the waves recorded at these receivers. We present a derivation of this principle based on the method of stationary phase. Although this derivation is intended to be educational, applicable to simple media only, it provides insight into the physical principle of seismic interferometry. In a homogeneous medium with one horizontal reflector and without a free surface, the correlation of the waves recorded at two receivers correctly gives both the direct wave and the singly reflected waves. When more reflectors are present, a product of the singly reflected waves occurs in the crosscorrelation that leads to spurious multiples when the waves are excited at the surface only. We give a heuristic argument that these spurious multiples disappear when sources below the reflectors are included. We also extend the derivation to a smoothly varying heterogeneous background medium.
261 citations
Patent•
31 Dec 2001TL;DR: In this article, the authors describe a reflector network consisting of a hierarchy of reflectors that are located at various entry points into the CDN, at each edge node at which requesting users may be directed to obtain live streams, and at various'reflector' nodes located within at least one intermediate layer (in the hierarchy) between the entry points and the edge nodes.
Abstract: A reflector network is used within a content delivery network to enable requesting end users to subscribe to live streams that have been published to CDN entry points. A reflector is a generalized packet router program. The reflector network preferably comprises a hierarchy of reflectors that are located at the various entry points into the CDN, at each edge node at which requesting users may be directed by the CDN to obtain live streams, and at various 'reflector' nodes located within at least one intermediate layer (in the hierarchy) between the entry points and the edge nodes. The edge nodes and each reflector node also include a manager program that arranges for feeds. When an end user is directed to an edge node that is not yet receiving the desired stream, the edge node's manager issues a subscription request to a set of reflector nodes. If the reflector node(s) are already receiving the desired stream, their reflector(s) begin sending it to the requesting edge node. If, however, the reflector node(s) are not already receiving the desired stream, their manager programs issue the subscription request to the entry point(s) to start the feed.
261 citations
Patent•
16 Jun 2006
TL;DR: In this paper, an indoor millimeter-wave wireless personal area network (PAN) is described, where a directional antenna (103) and a diffusive reflector (106) are used to increase throughput and reduce multipath components.
Abstract: Embodiments of an indoor millimeter-wave wireless personal area network and method are described. In some embodiments, a directional antenna (103) and a diffusive reflector (106) are used to increase throughput and reduce multipath components.
258 citations
TL;DR: By designing the reflectance and the phase of non-periodic HCGs, both focusing reflectors and lenses can be constructed and HCG optics can simultaneously focus the reflected and transmitted waves, with important technological implications.
Abstract: We propose planar, high numerical aperture (NA), low loss, focusing reflectors and lenses using subwavelength high contrast gratings (HCGs). By designing the reflectance and the phase of non-periodic HCGs, both focusing reflectors and lenses can be constructed. Numerical aperture values as high as 0.81 and 0.96 are achieved for a reflector and lens with very low losses of 0.3 and 0.2 dB, respectively. The design algorithm is also shown to be readily extended to a 2D lens. Furthermore, HCG optics can simultaneously focus the reflected and transmitted waves, with important technological implications. HCG focusing optics are defined by one-step photolithography and thus can be readily integrated with many devices including VCSELs, saturable absorbers, telescopes, CCDs and solar cells.
257 citations