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Visar resultat 11 - 15 av 60 avhandlingar som matchar ovanstående sökkriterier.

  1. 11. 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. 12. Low-Noise Amplifier Design for Ultra-Wideband Systems

    Författare :Adriana Serban Craciunescu; Linköpings universitet; []
    Nyckelord :TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : The low-noise amplifier (LNA) remains a critical block in every receiver front-end. As the development of the widcband, low-power and low-cost wireless systems continues, new LNA topologies and design methodologies have become one of the most interesting challenges in the field of radio frequency system design. LÄS MER

  4. 13. On the Physical Layer of Ultra-Wideband Systems

    Författare :Matts-Ola Wessman; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : This licentiate thesis consists of two published conference papers, onetechnical report, and an introduction. The focus is on communication at bitrates of 100 Mbps and higher for single-user systems at short range up to 10meters. LÄS MER

  5. 14. THz Ultra-wideband Passive Devices: Design, Simulation and Characterization

    Författare :Cristian Daniel López; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Superconducting Transition; Substrateless Finline; Compact waveguide twist; Marchand Baluns.; Broadband Waveguide to Substrate Transition;

    Sammanfattning : The last decades have seen an increasing interest in the THz research field, leading to a substantial improvement in technology and the emergence of new applications. In particular, the research on radio astronomy instrumentation has pushed millimeter and sub-millimeter technology boundaries and redefined state of the art. LÄS MER

  7. 15. Sub-Nyquist Sampling Impulse Radio UWB Receivers for the Internet-of-Things

    Författare :Qin Zhou; Hannu Tenhunen; Li-Rong Zheng; Qiang Chen; Kari Halonen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultra-Wideband; impulse radio; receiver; energy detection; compressed sensing; sub-Nyquist sampling; Internet-of-Things; Informations- och kommunikationsteknik; Information and Communication Technology;

    Sammanfattning : In the era of Internet-of-Things, the demand for short range wireless links featured by low-power and low-cost, robust communication and high-precision positioning is growing rapidly. Impulse Radio Ultra-Wideband (IR-UWB) technology characterized by the transmission of sub-nanosecond pulses spanning up to several GHz band with extremely low power spectral density emerges as a promising candidate. LÄS MER