Sökning: "sub 6 GHz"

Visar resultat 1 - 5 av 17 avhandlingar innehållade orden sub 6 GHz.

  1. 1. Massive MIMO From a Terminal Perspective

    Detta är en avhandling från Department of Electrical and Information Technology, Lund University

    Författare :Erik L Bengtsson; Lund University.; Lunds universitet.; Lund University.; Lunds universitet.; [2019-09-03]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Massive MIMO; mm-wave; terminal antenna; channel sounding; Propagation Channel; sub 6 GHz;

    Sammanfattning : This thesis focuses on the terminal aspects of massive MIMO systems. Based on the degree of freedom a terminal have in a MaMi, different antenna configurations, transceiver topologies with associated transmission schemes, and the underlying algorithms are researched. LÄS MER

  2. 2. Low Noise SIS Mixers and Cryogenic Amplifiers for Sub-Millimeter Astronomy

    Detta är en avhandling från Department of Electrical and Information Technology, Lund University

    Författare :Christophe Risacher; [2005]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This PhD thesis presents the work that was done developing radioastronomy instrumentation. The first part of this work deals with 2-stage low-noise cryogenic amplifiers using commercial GaAs HEMT transistors for frequency bnads: 3.4-4.6 GHz, 4-8 GHz and 8-9 GHz. LÄS MER

  3. 3. Nonlinear optics in KTiOPO4 for spectral management of ultra-short pulses in the near- and mid-IR

    Detta är en avhandling från KTH Royal Institute of Technology

    Författare :Anne-Lise Viotti; KTH.; [2019]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nonlinear optics; Ferroelectrics; Physics; Fysik;

    Sammanfattning : This thesis explores the possibilities of controlling nonlinear optical interactions in ferroelectric materials for bandwidth tailoring of ultrashort pulses in the pico- and femto-second range. The control is achieved through quasi-phase matching, which is based on alternating the material’s spontaneous polarization into different domains. LÄS MER

  4. 4. Resonant switching and vortex dynamics in spin-flop bi-layers

    Detta är en avhandling från Stockholm : KTH

    Författare :Sergiy Cherepov; KTH.; [2010]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spin-dynamics; MRAM; vortex; switching; NATURAL SCIENCES Physics Condensed matter physics; NATURVETENSKAP Fysik Kondenserade materiens fysik; NATURAL SCIENCES Physics Condensed matter physics Magnetism; NATURVETENSKAP Fysik Kondenserade materiens fysik Magnetism; NATURAL SCIENCES Physics Condensed matter physics Mesoscopic physics; NATURVETENSKAP Fysik Kondenserade materiens fysik Mesoskopisk fysik;

    Sammanfattning : This thesis is a study of the static and dynamic behavior of the magne-tization in spin-flop bi-layers, which consist of two soft ferromagnetic layerscoupled by dipolar forces through a thin nonmagnetic spacer. The focus ofthe work is three fold: collective spin dynamics in the anti-parallel groundstate; resonant switching in the presence of thermal agitation; and static anddynamic behavior of the system in the vortex-pair state, with a particularemphasis on the interlayer core-core interaction. LÄS MER

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

    Detta är en avhandling från The Department of Electrical and Information Technology

    Författare :Jonas Lindstrand; Lund University.; Lunds universitet.; Lund University.; Lunds universitet.; Lund University.; Lunds universitet.; [2019-10-15]
    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