Sökning: "multiple antennas"

Visar resultat 26 - 30 av 150 avhandlingar innehållade orden multiple antennas.

  1. 26. User Effect Mitigation in MIMO Terminal Antennas

    Författare :Ivaylo Vasilev; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : The rapid growth of cellular technology over the past decade transformed our lives, enabling billions of people to enjoy interactive multimedia content and ubiquitous connectivity through a device that can fit into the palm of a hand. In part the explosive growth of the smartphone market is enabled by innovative antenna system technologies, such as multiple-input multiple-output (MIMO) systems, facilitating high data rates and reliable connections. LÄS MER

  3. 27. Online power transformer diagnostics using multiple modes of microwave radiation

    Författare :Mariana Dalarsson; Martin Norgren; Sven Nordebo; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; inverse problem; multiple modes; power transformers;

    Sammanfattning : In the present thesis, we propose and investigate a new approach to diagnose the effects of the various degradation mechanisms, including thermal degradation at hot spots, winding deformations due to the mechanical forces from short circuit currents, partial discharges due to local electric field surges, and increased moisture levels in the cellulose insulation due to decomposition, that affect electric power transformers during their normal operation in an electric power grid.Although the proposed diagnostics method can in principle be used to detect various degradation mechanisms mentioned above, we focus in the present thesis on mechanical deformations of transformer winding structures. LÄS MER

  4. 28. Over-the-Air Performance Estimation of Wireless Device Antennas

    Författare :Sathyaveer Prasad; Peter Händel; Gert Frölund Pedersen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : This thesis work presents studies on the available measurement methods for estimating the over-the-air (OTA) performance of wireless device antennas. This thesis is divided into two parts. LÄS MER

  5. 29. Analysis of Radio Channel Measurements Using Multiple Base Stations

    Författare :Niklas Jaldén; Björn Ottersten; Bo Göransson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Channel Modellin; Telecommunication; Telekommunikation;

    Sammanfattning : Future wireless communication systems will utilize the spatial properties of the wireless channel to improve the spectral efficiency and thus increase capacity. This is realized by deploying multiple antennas at both the transmitter and receiver. LÄS MER

  7. 30. Robust Vehicular Communications for Traffic Safety---Channel Estimation and Multiantenna Schemes

    Författare :Keerthi Nagalapur; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Traffic Safety; Sector Antennas; All-to-all Broadcast; Channel Estimation; Cross-layer Pilot Scheme; Multiantenna Schemes; Vehicular Communications V2X ;

    Sammanfattning : Vehicular communications, where vehicles exchange information with other vehicles or entities in the road traffic environment, is expected to be a part of the future transportation system and promises to support a plethora of applications for traffic safety and efficiency. In particular, vehicle-to-vehicle (V2V) communication promises to support numerous traffic safety applications by enabling a vehicle to broadcast its current status to all the other vehicles in its surrounding. LÄS MER