Search for dissertations about: "sub-millimeter"

Showing result 1 - 5 of 22 swedish dissertations containing the word sub-millimeter.

  2. 1. Millimeter and Sub-Millimeter Wave Integrated Active Frequency Down-Converters

    Author : Yu Yan; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 145 GHz; self-oscillating mixer; mixer; conversion gain; millimeter wave; radar; mHEMT; noise figure; monolithic; sub-millimeter wave; InP; THz; resistive mixer; Gilbert mixer; DHBT; SiGe; 340 GHz; 220 GHz; FMCW; transconductance mixer; BiCMOS; transceiver; harmonic; GaAs;

    Abstract : In recent years, the increasing amount of data transmission, the need for automotiveradars, and standoff imaging for security applications are the main factors that accelerateresearch in the millimeter and sub-millimeter wave frequency ranges. The semiconductorindustries have continuously developed their processes, which have opened upopportunities for manufacturing monolithically integrated circuits up to a few hundredGHz, based on transistor technologies. READ MORE

  4. 2. Planar Quasiparticle Mixer Structures for Millimeter and Sub-Millimeter Wave Receivers

    Author : Anders Skalare; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; SIS receiver; dipole array antenna; slot substrate mode loss; millimeter wave regime; planar antennas; sub-millimeter wave regime; superconducting mixers; slot radiation; slot lines; slot wavelengths; Voltage Matching Method;

    Abstract : The paper covers various aspects of integrating planar antennas with superconducting mixers in the millimeter and sub-millimeter wave regime. The construction of an 80-100 GHz tapered slot antenna and SIS mixer chip with a minimum double side band noise temperature of 240 K is described. READ MORE

  5. 3. Stacking of interferometric data at sub-millimeter and radio wavelengths

    Author : Lukas Lindroos; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; techniques: interferometric; methods: data analysis; sub-millimetre: galaxies; galaxies: high- redshift; radio continuum: galaxies;

    Abstract : Understanding the procceses of galaxy evolution require observational constraints on the physical properties of galaxies at different times in the history of the Universe. Large and deep surveys at visible and near-infrared wavelengths have, during the past decade, been used to produce extensive catalogues of high-redshift galaxies, spanning a large range of the history of the Universe. READ MORE

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

    Author : Christophe Risacher; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : 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. READ MORE

  7. 5. Remote sensing of clouds and precipitation using active and passive microwave observations

    Author : Simon Pfreundschuh; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Microwave remote sensing; precipitation; clouds; hydrometeors;

    Abstract : Global observations of clouds and precipitation are of great importance for weather prediction and the monitoring of the climate. Nonetheless, the currently available record of global observations does not constrain the properties of clouds very well owing to the inherent limitations of the observation systems used to produce them. READ MORE