Sökning: "Antenna performance"

Visar resultat 1 - 5 av 221 avhandlingar innehållade orden Antenna performance.

  1. 1. Investigating and Enhancing Performance of Multiple Antenna Systems in Compact MIMO/Diversity Terminals

    Författare :Shuai Zhang; Sailing He; Raj Mittra; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multiple antennas; planar inverted-F antenna; mutual coupling; slot antenna; compact antenna; mobile antenna; Q factors; antenna array; ultra-wideband UWB antenna; pattern diversity; polarization diversity; user effects; adaptive arrays; chassis mode;

    Sammanfattning : Today, owners of small communicating device are interested in transmitting or receiving various multimedia data. By increasing the number of antennas at the transmitter and/or the receiver side of the wireless link, the diversity/Multiple-Input Multiple-Output (MIMO) techniques can increase wireless channel capacity without the need for additional power or spectrum in rich scattering environments. LÄS MER

  2. 2. Systematic Antenna Design Using the Theory of Characteristic Modes

    Författare :Zachary Miers; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Theory of Characteristic Modes; Antenna Design; Antenna; Characteristic Modes; Computational Electromagnetics; MIMO Systems; MIMO Antenna; MIMO; Mutual Coupling; Mobile Antenna;

    Sammanfattning : The day Faraday moved a magnet in and out of a wire loop and detected the time-varying magnetic field, the first wireless transmitter / receiver system was created and the world was changed forever. However, it took almost fifty years for Heinrich Hertz to use Maxwell's equations and Faraday's insights in his professorship at Karlsruhe to create the first electromagnetic wireless communication system using a spark gap dipole transmitter and a loop antenna-based receiver. LÄS MER

  3. 3. Antenna Integrated Superconducting Mixers

    Författare :Hans Ekström; Chalmers University of Technology; []
    Nyckelord :tapered slotline antenna; mixer; double dipole antenna; superconducting; hot electron; receiver; Niobium; bolometer; trilayer junction; edge junction; Niobium Nitride; SIS;

    Sammanfattning : This thesis investigates the prospects of some different superconducting mixers integrated with planar antennas for the millimeter and submillimeter regime. Two kinds of Superconductor/Insulator/Superconductor (SIS) tunnel junctions for use in mixers have been fabricated; Nb/PbBi edge junctions and Nb trilayer junctions. LÄS MER

  4. 4. Modeling of a Retrodirective Channel With Active Antenna Arrays for Cross-Eye Jamming

    Författare :Björn Petersson; Martin Norgren; Warren P. du Plessis; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; electronic warfare; antenna array; antenna system; radar countermeasures; jamming; cross-eye; systems modeling; system performance; systems simulation; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Cross-Eye (CE) jamming is a technique aimed at inducing false target angles in radar measurements. The potential to deceive monopulse radar, a radar type commonly used due to its angular accuracy and resilience against jamming, has captured the interest of Electronic Warfare (EW) system manufacturers. LÄS MER

  5. 5. Estimation and Performance Analysis of Wireless Multiple Antenna Communication Channels

    Författare :Mikael Coldrey; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MIMO; generalized beamforming; Wireless communications; training; channel estimation; distributed sources; capacity; performance bounds;

    Sammanfattning : The focus of this thesis is on channel estimation in wireless communication systems that employ multiple antennas.The thesis is divided into two parts, whereof the first part addresses theproblem of parameter estimation of distributed sources. Due to, e.g. LÄS MER