Search for dissertations about: "frequency bands"

Showing result 1 - 5 of 143 swedish dissertations containing the words frequency bands.

  2. 1. Frequency Selective Cold-Electron Bolometer Arrays

    Author : Sumedh Mahashabde; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; mm-wave detectors; Cold-Electron Bolometer; Frequency Selective Surface; Focal Plane array; OLIMPO; LSPE;

    Abstract : This work presents the integration of the Cold-Electron Bolometer (CEB) in Frequency Selective Surface (FSS) based arrays targeting balloon-borne telescope missions with high incident power requirements (typically tens of pW). FSS are planar frequency sensitive structures typically consisting of repeating pattern of a simple motif like square, circle, etc. READ MORE

  4. 2. Optical Frequency Comb Fourier Transform Spectroscopy

    Author : Alexandra C. Johansson; Aleksandra Foltynowicz; Ove Axner; Jürgen Röpcke; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Optical frequency comb spectroscopy; Fourier transform; molecular absorption dispersion; fysik; Physics;

    Abstract : Fourier transform spectroscopy (FTS) based on optical frequency combs is an excellent spectroscopic tool as it provides broadband molecular spectra with high spectral resolution and an absolutely calibrated frequency scale. Moreover, the equidistant comb mode structure enables efficient coupling of the comb to enhancement cavities, yielding high detection sensitivity. READ MORE

  5. 3. Design of Reliable Communication Solutions for Wireless Sensor Networks : Managing Interference in Unlicensed Bands

    Author : Luca Stabellini; Jens Zander; Andreas Kassler; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Telecommunication; Telekommunikation;

    Abstract : Recent surveys conducted in the context of industrial automation have outlined that reliability concerns represent today one of the major barriers to the diffusion of wireless communications for sensing and control applications: this limits the potential of wireless sensor networks and slows down the adoption of this new technology. Overcoming these limitations requires that awareness on the causes of unreliability and on the possible solutions to this problem is created. READ MORE

  6. 4. Precision molecular spectroscopy in the near- and mid-infrared using frequency comb-based Fourier transform spectrometers

    Author : Adrian Hjältén; Aleksandra Foltynowicz; Ove Axner; Adam Fleisher; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; optical frequency comb; molecular spectroscopy; Fourier transform spectrometer; high resolution; mid-infrared; line list; double-resonance spectroscopy; difference frequency generation; fysik; Physics;

    Abstract : Absorption spectroscopy is a powerful scientific tool for non-invasive and remote sensing applications ranging from atmospheric monitoring to astrophysics. In spectroscopic detection schemes it is necessary to have spectral models for any molecular species to be detected or quantified. READ MORE

  7. 5. High spectral efficiency transmission using optical frequency combs

    Author : Mikael Mazur; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Optical frequency combs; Superchannels; Coherent optical communication;

    Abstract : Modern long-haul optical communication systems transmit data on all available single-mode fiber dimensions, time, polarization, wavelength, phase and amplitude. Powerful digital signal processing and forward error correction has pushed the per-channel throughput towards its theoretical limits and the bandwidth is limited by the erbium-doped fiber amplifiers. READ MORE