985 resultados para Antennas (Electronics)


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Aim of this contribution is to illustrate the state of the art of smart antenna research from several perspectives. The bow is drawn from transmitter issues via channel measurements and modeling, receiver signal processing, network aspects, technological challenges towards first smart antenna applications and current status of standardization. Moreover, some future prospects of different disciplines in smart antenna research are given.

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The practical applications of microstrip antennas for mobile systems are in portable or pocket-size equipment and in vehicles. Antennas for VHFIUHF handheld portable equipment, such as pagers, portable telephones and transceivers, must naturally be small in size, light in weight and compact in structure. There is a growing tendency for portable equipment to be made smaller and smaller as the demand for personal communication rapidly increases, and the development of very compact hand-held units has become urgent.In this thesis work, main aim is to develop a more and more reduced sized microstrip patch antenna. It is well known that the smaller the antenna size, the lower the antenna efficiency. During the period of work, three different compact circular sided microstrip patches are developed and analysed, which have a significant size reduction compared to standard circular disk antenna (the most compact one of the basic microstrip patch configurations), without much deterioration of its properties like gain, bandwidth and efficiency. In addition to this the interesting results, dual port operation and circular polarization are also observed for some typical designs of these patches. These make the patches suitable for satellite and mobile communication systems.The theoretical investigations are carried out on these compact patches. The empirical relations are developed by modifying the standard equations of rectangular and circular disk microstrip patches, which helps to predict the resonant frequencies easily.

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Includes bibliographical references (76-77)

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"Contract No. AF33(616)-3220 Project No. 6(7-4600) Task 40572 Wright Air Development Center"

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"Contract AF33(616)-6079 Project No. 9-(13-6278) Task 40572. Sponsored by: Wright Air Development Center"

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Includes bibliography (leaf 11).

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"Contract No. AF33(616)-3220 Project No. 6(7-4600) Task 40572 Wright Air Development Center"

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Mode of access: Internet.

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"Technical report AFAL-TR-65-267"

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The authors have demonstrated an optical fibre grating based delay line which produces time delays in increments as small as 31 ps. The device could provide a true time delay component for a phased array antenna

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Aquest document de treball es centra específicament en el desenvolupament de la infraestructura de telefonia mòbil a Catalunya com a exemple de tecnologia amb profundes implicacions socials. Esdevé un intent inicial de definir les principals línies de recerca en aquest tema. El projecte que el sosté és emmarcat en el programa de recerca Negrisc, centrat a examinar la negociació del risc en les tecnologies de la informació i de la comunicació. Parteix d'una aproximació que reconeix la natura multidisciplinària del risc i que, per tant, exigeix una aproximació interdisciplinària al seu estudi i a la gestió subsegüent. Aquesta perspectiva emfatitza la necessitat d'integrar els punts de vista dels diferents stakeholders, incloent-hi el públic, en la gestió d'una tecnologia socialment controvertida. Aquest és un pas necessari per a permetre la generació d'algun tipus de consens en el cas del desenvolupament de la infraestructura de telefonia mòbil a Catalunya.

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At head of title: Antenna Laboratory.

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"Contract AF33(616)-3220 Project No. 6(7-4600), Task No. 40572, Wright Air Development Center."

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"Contract No. AF33(616)-3220 Project No. 6(7-4600) Task 40572 Wright Air Development Center"