Sökning: "radio telescopes"

Visar resultat 1 - 5 av 23 avhandlingar innehållade orden radio telescopes.

  1. 1. Ultra-wideband feed design and characterization for next generation radio telescopes

    Författare :Jonas Flygare; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reflector feed; geodesy; radio astronomy; quad-ridge flared horn; square kilometre array; dielectric loading; spline-defined; decade bandwidth; Ultra-wideband antennas;

    Sammanfattning : Radio telescopes are used as tools for observations in both radio astronomy and geodesy. To observe the weak sources in space, highly sensitive receivers headed by optimized reflector feeds are needed. Wideband and ultra-wideband (UWB) receiver systems enable large continuous frequency bandwidth and reduce the number of receivers that are needed. LÄS MER

  3. 2. Digital Beamforming Focal Plane Arrays for Radio Astronomy and Space-Borne Passive Remote Sensing

    Författare :Oleg Iupikov; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; beamforming; spaceborne radiometers; radio telescopes; phased array feeds; reflector antenna feeds; feed-reflector interaction;

    Sammanfattning : Dense Phased Array Feeds (PAFs) for reflector antennas have numerous advantages over traditional cluster feeds of horns in a one-horn-per-beam configuration, especially in RF-imaging applications which require multiple simultaneously formed and closely overlapping beams. However, the accurate analysis and design of such PAF systems represents a challenging problem, both from an EM-modeling and beamforming optimization point of view. LÄS MER

  4. 3. Dielectrically Loaded Quad-ridge Flared Horns for Ultra Wideband Reflector Feed Applications in Radio Astronomy

    Författare :Jonas Flygare; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric loaded antennas; dielectric materials; reflector antenna feeds; radio astronomy; ultra wideband antennas; quad-ridge flared horn qrfh ; radio receivers; horn antennas; broadband antennas; aperture antennas.;

    Sammanfattning : Reflector-based radio telescopes are used as tools for observations in both radio astronomy and space geodesy. To observe the weak sources in space, highly sensitive receivers, fronted by optimized reflector feeds, are therefore needed. LÄS MER

  5. 4. Stacking of interferometric data at sub-millimeter and radio wavelengths

    Författare :Lukas Lindroos; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; techniques: interferometric; methods: data analysis; sub-millimetre: galaxies; galaxies: high- redshift; radio continuum: galaxies;

    Sammanfattning : Understanding the procceses of galaxy evolution require observational constraints on the physical properties of galaxies at different times in the history of the Universe. Large and deep surveys at visible and near-infrared wavelengths have, during the past decade, been used to produce extensive catalogues of high-redshift galaxies, spanning a large range of the history of the Universe. LÄS MER

  7. 5. High-resolution radio imaging of galaxy nuclei

    Författare :Eskil Varenius; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arp220; star formation; NGC4418; M82;

    Sammanfattning : Star formation and galaxy evolution are intimately linked together. A detailed understanding of the environment where stars form may help us explain the differences we see between galaxies today and at earlier times in the history of the Universe. LÄS MER