Sökning: "near-field measurements"

Visar resultat 1 - 5 av 39 avhandlingar innehållade orden near-field measurements.

  1. 1. Characterization and Design Requirements for Antennas in the Near-field and the Random-LOS Propagation Environment

    Författare :Aidin Razavi; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; polarization-MIMO; Random-LOS; OTA; Antenna measurements; near-field antennas; antenna characterization; MIMO; near-field focusing;

    Sammanfattning : The choice of antenna for a particular application depends on the requirements imposed by that application. These can be, the application's field region (i.e., near-field or far-field), polarization, radiation pattern, radiation efficiency, system throughput, etc. LÄS MER

  2. 2. Near-Field Study of Multiple Interacting Jets : Confluent Jets

    Författare :Shahriar Ghahremanian; Bahram Moshfegh; Högskolan i Gävle; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multiple interacting jets; confluent jets; axisymmetric round jet; Low Reynolds number jet; Particle Image Velocimetry PIV ; Laser Doppler Anemometry LDA ; Hot-Wire anemometry HWA ; RANS turbulence models; SST −; Low Reynolds −; Response Surface Method; SST ? − ?; Low Reynolds ? − ?;

    Sammanfattning : This thesis deals with the near-field of confluent jets, which can be of interest in many engineering applications such as design of a ventilation supply device. The physical effect of interaction between multiple closely spaced jets is studied using experimental and numerical methods. LÄS MER

  3. 3. Photonic terahertz-wave generation, radiation and quasioptical integration

    Författare :Biddut Kumar Banik; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; semiconductor device modelling; semiconductor diodes; III-V semiconductors; Catadioptric lens; imaging; dipole antennas; slot antennas; lens antennas; semiconductor heterojunctions; dielectric loaded antennas; optical mixers; photomixers; near-field imaging; computer aided engineering; indium compounds; millimetre wave imaging; near-field optics; submillimeter wave generation; photodiodes; terahertz sources; millimetre wave generation; submillimetre wave integrated circuits; microwave imaging; uni-travelling-carrier photodiodes;

    Sammanfattning : This thesis deals with the uni-travelling-carrier photodiode (UTC-PD) based photonic generation of terahertz waves, antenna designs for the terahertz radiation and a novelcatadioptric lens for quasioptical integration.The ongoing and accomplished research work on the UTC-PD, its limitations and optimisation scopes for attaining higher bandwidth and higher output power have been discussed. LÄS MER

  4. 4. Design of Functional Structures and Measurement Techniques for Electromagnetic Waves

    Författare :Johan Lundgren; Teoretisk elektroteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; functional structures; frequency selective structures; polarization selectivity; metasurface; near-field measurements; antenna measurements; scattering measurement; power density; random media;

    Sammanfattning : Electromagnetic fields exist all around us. Through evolution, nature has developed tools to interact and use these fields, where our eyes are a spectacular example. Humans have a long history of developing structures and objects of their own to alter and interact with these fields. LÄS MER

  5. 5. Prerequisites for Efficient Programming of RFID Inlays in Reactive Near Field

    Författare :Markus Frank; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; FOM; RNF; RFID; UHF.; Source Impedance Shift; DTLL; Phase compensation;

    Sammanfattning : The electromagnetically isolated programming of unique user IDs, into the transponder memory of UHF RFID inlays, is essential for successful operation in the RFID inventory process. Bar code printers enabled for RFID represent a typical environment of such programming. LÄS MER