Sökning: "decade bandwidth"

Visar resultat 1 - 5 av 28 avhandlingar innehållade orden decade bandwidth.

  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. Development of the Eleven Antenna - A Decade Bandwidth Feed for Reflector Antennas

    Författare :Rikard Olsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Recently there has been a growing interest in reducing the number of antennas on different platforms by combining several functions in the same antenna. To achieve this, the multifunction antenna needs to be either very broadband or multi band to cover the frequencies of all functions. LÄS MER

  4. 3. Multicarrier Faster-than-Nyquist Signaling Transceivers: From Theory to Practice

    Författare :Deepak Dasalukunte; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; iterative decoding; bandwidth efficient; Faster-than-Nyquist; hardware architecture; multicarrier;

    Sammanfattning : The demand for spectrum resources in cellular systems worldwide has seen a tremendous escalation in the recent past. The mobile phones of today are capable of being cameras taking pictures and videos, able to browse the Internet, do video calling and much more than an yesteryear computer. LÄS MER

  5. 4. Integrated Transmitters for Cellular User Equipment–Wideband CMOS Power Amplifiers and Antenna Impedance Tuners

    Författare :Jonas Lindstrand; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CMOS; LTE; Impedance tuner; Injection lock; Power amplifier; Efficiency; Polar bandwidth expansion; multiband;

    Sammanfattning : The digital cellular systems era started about thirty years ago with the release of the first digital cellphones. These first digital cellphones were very different from today’s slim and esthetic cellular pocket computers. They were not mass-produced in million units a day, and they were designed for radio performance rather than appearance. LÄS MER

  7. 5. Baluns, Hybrids and Power Dividers for Ultra- Wideband Antennas

    Författare :Syed Hasan Raza Zaidi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multiport feeding network; baluns; packaging; power divider; Ultra-wideband; Eleven feed; gap waveguide; ring hybrid.;

    Sammanfattning : UWB (ultra wideband), depending on the application requirement, is usually referred to 2:1 bandwidth for radio/wireless applications. Here in this thesis it is also used to denote extremely wideband antenna and components at several octave bandwidth, particularly for high frequency applications, such as the 1 – 10 GHz antenna system needed for the Square Kilometer Array (SKA) radio telescope and the 2 – 14 GHz antenna system for the VLBI2010 (Very Long Base line Interferometer) project. LÄS MER