Sökning: "reflector antennas"

Visar resultat 1 - 5 av 21 avhandlingar innehållade orden reflector antennas.

  1. 1. 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

  3. 2. Miniaturized Hard Waveguides in Multifunction Array Antennas

    Författare :Malcolm Ng Mou Kehn; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; interlaced arrays; Floquet theorem; reflector antennas; focal plane array; multifunction antennas; miniaturized waveguides; multilayer structures; spectral domain technique; periodic structures; aperture reuse; method of moments; soft and hard surfaces; array antennas;

    Sammanfattning : Recent advances in technologies of wireless communications systems have led to an increasing desire for several antennas performing diverse functions at different frequencies to be integrated into a common radiating aperture. This gives rise to the so-called multifunction antenna, which affords the saving of scarce premium real estate and can alleviate problems arising from excessive antenna protrusions in aspects such as aerodynamics, aesthetics, and stealth capability in military applications. LÄS MER

  4. 3. Design of hat fed reflector antennas using FDTD

    Författare :Jian Yang; Per-Simon Kildal; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; soft and hard surfaces; finite difference time domain FDTD method; sperture efficiencies; Gaussian vertex plate; corrugations; edge corrugations; hat feed antenna; phase center; vertex plate; ring-focus paraboloid; paraboloid; V2D code; ring-shaped phase center; BOR1 antenna; reflector shaping; reflector antenna;

    Sammanfattning : .... LÄS MER

  5. 4. Modern numerical methods in electromagnetics applied to the design of reflector antennas and horn feeds

    Författare :Martin Johansson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reflector antenna; cluster feed; offset; dual-reflector feed; mode matching; very long baseline interferometry; circular waveguide; diffraction; physical optics; corrugated horn; coaxial waveguide; VLBI; dual-frequency; low noise; finite element method; ray tracing; dual-band;

    Sammanfattning : .... LÄS MER

  7. 5. Space Geodesy Techniques: An Experimental and Theoretical Study of Antenna Related Error Sources

    Författare :R. T. Kenneth Jaldehag; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reflector antennas; signal scattering; very long baseline interferometry VLBI ; signal multipath; space geodesy; GPS error sources; geodetic networks; Global Positioning System GPS ; postglacial rebound; choke-ring antennas;

    Sammanfattning : This thesis presents work associated with antenna related error sources, as well as antenna design, in space geodesy utilizing the techniques of Very-Long-Baseline Interferometry (VLBI) and the Global Positioning System (GPS). Geodetic VLBI uses large radio telescopes, often in global networks observing at least a few times per year. LÄS MER