Sökning: "periodic structures"

Visar resultat 1 - 5 av 155 avhandlingar innehållade orden periodic structures.

  1. 1. Twist-Symmetric Periodic Structures : Properties and Applications

    Författare :Oskar Zetterström; Oscar Quevedo-Teruel; Martin Norgren; Nelson Fonseca; Jorge Ruiz-Cruz; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : In this thesis, periodic structures with higher symmetries symmetries are discussed. The main focus of the thesis is on twist symmetries. Importantly, the attractive properties of twist symmetries for the control of electromagnetic wave propagation are demonstrated. LÄS MER

  3. 2. Analysis of Conformal Antennas and Periodic Structures

    Författare :Silvia Raffaelli; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; method of moments; microstrip; corrugated surface; horn; Floquet; array; periodic; multilayer structure; finite difference time domain; dual-frequency; infinite; spectral domain analysis; conformal antenna;

    Sammanfattning : In the last decades much attention has been paid to the design of high-performance antennas. Accurate control of the radiation properties is very important in electromagnetic engineering applications. LÄS MER

  4. 3. Periodic Structures with Higher Symmetries: Analysis and Applications

    Författare :Fatemeh Ghasemifard; Martin Norgren; Oscar Quevedo-Teruel; Guido Valerio; Stefano Maci; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; periodic structures; higher symmetries; dispersion analysis; mode matching; generalized Floquet theorem; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : In this thesis, periodic structures with higher symmetries are studied. Their wave propagation characteristics are investigated and their potential applications are discussed. Higher-symmetric periodic structures are described with an additional geometrical operation beyond a translation operator. LÄS MER

  5. 4. Periodic structures and lumped elements in microwave passives

    Författare :Dan Kuylenstierna; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Passive elements; Lumped elements; Photonic bandgap; Metamaterial; MMIC; Electromagnetic bandgap; Ferroelectric; Quadrature hybrid; Quadrature power splitter; Balun; Periodic structures;

    Sammanfattning : The ambition of this work is the incorporation of ferroelectric varactors as tuneable elements in Si integrated circuits (ICs). This thesis presents partialfulfillments of the work. LÄS MER

  7. 5. Acoustic excitation and transmission of lightweight structures

    Författare :Jonas Brunskog; Teknisk akustik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; point mobility; Lamb waves; wood.; Building construction; plate excitation; cavities; near-periodicity; nearly periodic; sound insulation; timber; structural acoustics; spatial Fourier transform; resilient device; prediction model; periodic; lightweight; ISO tapping machine; airborne noise; Building acoustics; impact noise; Byggnadsteknik;

    Sammanfattning : In order to increase our knowledge of the sound transmission and radiation processes of lightweight wall and floor structures, theoretical models are needed. Detailed models may form a valuable tool. In lightweight floor structures, impact sound insulation is perhaps the most important property to consider. LÄS MER