Sökning: "Small antennas"

Visar resultat 21 - 25 av 91 avhandlingar innehållade orden Small antennas.

  1. 21. Big Lessons from Small Bacteria : Following Photo-driven Processes in Photosynthetic Systems with Multidimensional Spectroscopy

    Författare :Egle Bukarte; Kemisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Two-dimensional electronic spectroscopy; Ultrafast spectroscopy; Chlorophyll; Bacterial reaction centers; Photosynthetic unit; Purple bacteria; Green bacteria;

    Sammanfattning : Sunlight is a plentiful, continuously flowing source of energy, fuelling life on Earth as we know it. To use this potential, plants, cyanobacteria and photosynthetic bacteria evolved to absorb solar radiance and convert it into a chemically stable form by performing a process known as photosynthesis. LÄS MER

  3. 22. 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

  4. 23. Tinkering with Light at the Nanoscale using Plasmonic Metasurfaces and Antennas: From Fano to Function

    Författare :Mikael Svedendahl; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; biosensing; Fano resonances; metamaterials; Surface plasmons;

    Sammanfattning : Surface plasmons are charge density oscillations that can couple strongly to light and be excited in, for instance, thin metal films and metal nanoparticles. The plasmonic excitation squeezes the light down to nanometric length scales, far smaller than the wavelength of the light. LÄS MER

  5. 24. EM Design for New Ultra Wide Band Technologies: Eleven Feed Baluns, Bowtie Antennas and Gap Waveguides

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

    Sammanfattning : UWB (ultra wideband), depending on the application requirement, is usually referred to more than 500 MHz bandwidth for radio/wireless applications. Here in this thesis it is also used to denote extremely wideband antennas and components of several octaves bandwidth, particularly for high frequency applications. LÄS MER

  7. 25. Characterization of Terminal Antennas for Diversity and MIMO Systems by Theory, Simulations and Measurements in Reverberation Chamber

    Författare :Kent Rosengren; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; mode stirred chamber; embedded pattern; channel capacity; radiation efficiency; reverberation chamber; embedded element; MIMO; diversity gain;

    Sammanfattning : This thesis is based on the work of designing and building a small reverberation chamber, and to use this chamber for characterization of antennas on mobile terminals such as phones. The characterization is done in terms of radiation efficiency, diversity gain and maximum available capacity. LÄS MER