Sökning: "directive antennas"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden directive antennas.

  1. 1. Topology optimization of antennas and waveguide transitions

    Författare :Emadeldeen Hassan; Martin Berggren; Daniel Noreland; Eddie Wadbro; Mats Gustafsson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Maxwell s equations; topology optimization; antennas; waveguide transition; finite-difference time-domain; gradient-based optimization; adjoint-field problem; microwave devices.; business data processing; administrativ databehandling;

    Sammanfattning : This thesis introduces a topology optimization approach to design, from scratch, efficient microwave devices, such as antennas and waveguide transitions. The design of these devices is formulated as a general optimization problem that aims to build the whole layout of the device in order to extremize a chosen objective function. LÄS MER

  3. 2. Antenna System Design for 5G and Beyond – A Modal Approach

    Författare :Hanieh Aliakbari Abar; Kommunikationsteknologi; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; millimeter-wave antennas; MIMO system; Modal analysis; Substrate integrated waveguide antennas; terminal antennas;

    Sammanfattning : Antennas are one of the key components that empower a new generation of wireless technologies, such as 5G and new radar systems. It has been shown that antenna design strategies based on modal theories represent a powerful systematic approach to design practical antenna systems with high performance. LÄS MER

  4. 3. Fully metallic antennas for millimeter wave applications

    Författare :Qingbi Liao; Oscar Quevedo-Teruel; Sean Victor Hum; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Modern societal demands for a high data throughput, short time latency and low energy consumption are difficult to satisfy using current wirelesscommunication techniques. The carrier frequency of previous wireless communication, such as broadcast, the global system for mobile communication, and wireless local area networks, are in the sub-3 GHz spectrum. LÄS MER

  5. 4. 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

  7. 5. EM Design for New Ultra Wide Band Technologies: Eleven Feed Baluns, Bowtie Antennas and Gap Waveguides

    Författare :Syed Hasan Raza Zaidi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultra-wideband; Eleven feed; gap waveguide; baluns; Multiport feeding network; power divider; ring hybrid.; packaging;

    Sammanfattning : UWB (ultra wideband), depending on the application requirement, is usually referred to more than 500 MHz bandwidth for radio/wireless applications. Here in this thesis it is also used to denote extremely wideband antennas and components of several octaves bandwidth, particularly for high frequency applications. LÄS MER