Sökning: "electrical impedance"

Visar resultat 21 - 25 av 240 avhandlingar innehållade orden electrical impedance.

  1. 21. Millimeter-Wave Active Array Antennas Integrating Power Amplifier MMICs through Contactless Interconnects

    Författare :Wan-Chun Liao; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; power amplifier; MMIC; Integrated active antenna; contactless transition;

    Sammanfattning : Next-generation mobile wireless technologies demand higher data capacity than the modern sub-6 GHz technologies can provide. With abundantly available bandwidth, millimeter waves (e.g., Ka/K bands) can offer data rates of around 10 Gbit/s; however, this shift to higher frequency bands also leads to at least 20 dB more free-space path loss. LÄS MER

  3. 22. Photonic THz Generation and Quasioptical Integration for Imaging Applications

    Författare :Biddut Kumar Banik; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nondestructive evaluation; semiconductor device modelling; uni-travelling-carrier photodiodes; millimetre wave and submillimetre wave generation; III-V semiconductors; photomixers; terahertz sources.; catadioptric lens; microwave imaging; dielectric loaded antennas; terahertz imaging; lens antennas; millimetre wave and submillimetre wave imaging;

    Sammanfattning : This thesis deals with the analysis and optimisation of the uni-travelling-carrier photodiode (UTC-PD) for continuous-wave generation in terahertz (THz) frequencyrange. Photonic THz generation using UTC-PDs is extremely promising as it offers wide tunability, adequate output power and room temperature operation. LÄS MER

  4. 23. Strontium Titanate-based Anodes for Solid Oxide Fuel Cells

    Författare :Peter Blennow Tullmar; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Kondenserade materiens egenskaper:elektronstruktur; spectroscopy; relaxation; magnetic resonance; supraconductors; magnetic and optical properties; electrical; Condensed matter:electronic structure; fasjämvikt; egenskaper termiska och mekaniska ; kristallografi; phase equilibria; Kondenserade materiens egenskaper:struktur; Condensed matter:stucture; thermal and mechanical properties; crystallography; infiltration; surfactant; ceria; Gd-doped ceria; redox stability; SOFC; ceramic anode; XRD; XANES; electrochemical impedance spectroscopy; defect chemistry; Nb-doped SrTiO3; electron microscopy; egenskaper elektriska; magnetiska och optiska ; supraledare; magnetisk resonans; spektroskopi; Inorganic chemistry; Oorganisk kemi; Electrochemistry; Elektrokemi; Energy research; Energiforskning; Composite materials; Kompositmaterial; Ceramic materials and powders; Keramiska material och pulver;

    Sammanfattning : The purpose for this work has been to develop new robust fuel electrodes for solid oxide fuel cells (SOFC). The aim was to find suitable ceramic materials or composites with promising properties for the use as SOFC anodes. LÄS MER

  5. 24. Electrical Bioimpedance Cerebral Monitoring : Effects of Hypoxia

    Författare :Fernando Seoane; Kaj Lindecrantz; Orjan Martinsen; University of Borås; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : Electrical bioimpedance spectroscopy is one way to study the electrical properties of biological matter. Different applications of electrical bioimpedance measurements have already been used in both research and clinical scenarios i.e. impedance plethysmography, total body water contents, etc. LÄS MER

  7. 25. The Effects of Lightning on Low Voltage Power Networks

    Författare :Raul Montaño; Vernon Cooray; Marcos Rubinstein; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Lightning induced effects; Lightning Electromagnetic fields; Electromagnetic Compatibility EMC ; Surge Protective Devices SPDs ; Low voltage power networks; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : The present society is highly dependant on complex electronics systems, which have a low damage threshold level. Therefore, there is a high risk of partial or total loss of the system’s electronics when they are exposed to a thunderstorm environment. LÄS MER