Sökning: "Q-factor"

Visar resultat 1 - 5 av 24 avhandlingar innehållade ordet Q-factor.

  1. 1. Antenna Limitations and Q-factor Trade-off between Parameters, Steps towards Optimal Antenna Design

    Författare :Shuai Shi; Lars Jonsson; Ala Sharaiha; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Antenna limitation; Q-factor; directivity; radiation pattern; current optimization; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Sub-wavelength antennas have become ubiquitous in essential devices, such as mobile phones, sensors, Internet of things (IoT) and machine to machine (M2M) communication devices. Such antennas are often embedded as a small part of the device chassis or their circuit-boards. LÄS MER

  3. 2. Fundamental Bounds on Performance of Periodic Electromagnetic Radiators and Scatterers

    Författare :Andrei Ludvig-Osipov; B. Lars G. Jonsson; Christophe Caloz; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Q-factor; bandwidth; antenna arrays; periodic structures; physical bounds; physical limitations; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : In this thesis, the optimal bandwidth performance of periodic electromagnetic radiators and scatterers is studied. The main focus is on the development and application of methods to obtain fundamental physical bounds, relating geometrical parameters, frequency bandwidth, efficiency and radiation characteristics of periodic electromagnetic structures. LÄS MER

  4. 3. Optimal Performance of Advanced Radiating Structures

    Författare :Casimir Ehrenborg; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Physical Bounds; MIMO Communication; Computational Electromagnetics; Antenna Theory; Optimization Methods; Q-factor;

    Sammanfattning : Requirements on radiating structures are constantly increasing, demand for faster speed, smaller size, and higher reliability drives today's technical development. However, for electrically small structures, less than half-a-wavelength in size, performance is fundamentally limited by physical size. LÄS MER

  5. 4. On the Frequency and Q Factor Response of the Quartz Crystal Microbalance to Liquid Overlayers

    Författare :Michael Rodahl; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; piezoelectric effect; solid-liquid interface; sensors; protein adsorption; QCM; tribology; quartz crystal microbalance;

    Sammanfattning : The quartz crystal microbalance (QCM) is an ultra-sensitive weighing device. It consists of a piezoelectric quartz crystal, often in the form of a disk, which is sandwiched between a pair of evaporated electrodes. LÄS MER

  7. 5. Characterization of losses in ridge, groove and microstrip gap waveguides

    Författare :Elena Pucci; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : The gap waveguide is a new technology that recently has been presented as an attractive candidate for applications at millimeter and sub millimeter waves. The waveguide is generated in the gap between a smooth upper metal plate and a ridge (or a groove) in a textured lower metal plate. LÄS MER