Sökning: "cylindrical structure"

Visar resultat 1 - 5 av 63 avhandlingar innehållade orden cylindrical structure.

  1. 1. Analysis of Dipole and Patch Antennas in Cylindrical Structures

    Författare :Peter Slättman; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fourier transform; cross-section; patch; slot; arbitrary; EFIE; trough guide; cylindrical; dipole; moment method; antenna; aperture coupled;

    Sammanfattning : This thesis deals with the analysis of dipoles, patches, and aperture coupled patches located in an infinitely long cylindrical structure with arbitrary cross-section. The analysis exploits the two-dimensional nature of the structure by expanding all fields and currents in spatial harmonics along the cylinder axis, and solving the subsequent spectral two-dimensional problems by the moment method. LÄS MER

  3. 2. Moment Method Analysis of Antennas in Reverberation Chambers and Cylindrical Structures

    Författare :Ulf Carlberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cavity; spectral domain method; cylindrical structure; Ewald summation; Green s function; absorption cross section; moment method; reverberation chamber; antenna;

    Sammanfattning : This thesis is a collection of papers using the method of moments for numerical analysis. The papers can be divided into two main groups; a study of antennas in reverberationchambers, and a study of antennas in cylindrical structures.The reverberation chamber is a metal cavity for measuring antennas and other devices. LÄS MER

  4. 3. Moment Method Analysis of Antennas in Reverberation Chambers and Cylindrical Structures

    Författare :Ulf Carlberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; antenna; spectral domain method; reverberation chamber; Ewald summation; moment method; cavity; cylindrical structure; Green s function; absorption cross section;

    Sammanfattning : This thesis is a collection of papers using the method of moments for numerical analysis. The papers can be divided into two main groups; a study of antennas in reverberation chambers and a study of antennas in cylindrical structures.The reverberation chamber is a metal cavity for measuring antennas and other devices. LÄS MER

  5. 4. Ternary Block Copolymer - Water - "Oil" Systems: Effects of "Oil" Type and Block Size on Phase Behaviour and Structure

    Författare :Peter Holmqvist; Fysikalisk kemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; poly propylene oxide ; poly ethylene oxide ; poloxamer; micelles; lyotropic liquid crystals; SAXS; structure; phase behavior; self-assembly; block copolymers; amphiphiles; poly tetrahydrofurane ; Physical chemistry; Fysikalisk kemi;

    Sammanfattning : It has recently been established in our group that amphiphilic block copolymers consisting of a hydrophilic and a hydrophobic part can self-assemble in the presence of selective solvents (“water” and “oil”) into a variety of different solution and lyotropic liquid crystalline microstructures. The effects of the “oil” type, hydrophilic block size and hydrophobic block type on the phase behavior and microstructure of ternary isothermal copolymer - oil - water systems have been addressed in this thesis. LÄS MER

  7. 5. Cylindrical Waveguide Slot Antenna Analysis

    Författare :Johan Wettergren; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; basis function; mutual admittance; cylinder; MPIE; slot; integral equation; waveguide; antenna; mutual coupling; moment method; EFIE;

    Sammanfattning : Waveguide slot antennas with longitudinal and transverse slots are analyzed using a rigorous method. The antennas are divided into regions, which are analyzed separately and matched by a moment method procedure. At the apertures between the regions, the electric fields are expanded in trigonometric basis functions. LÄS MER