Sökning: "impedance plane"

Visar resultat 1 - 5 av 43 avhandlingar innehållade orden impedance plane.

  1. 1. Studies of sound generation and propagation in flow ducts

    Författare :Fabrice Ducret; Mats Åbom; Andy Moorhouse; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; two-port; plane wave; HVAC system; tailpipe; exhaust system; flexible duct; pipe; reflection coefficient; impedance; flow noise; vorticity; damping; scaling laws; impedance; transmission loss; perforated plate; slit; non linearity; Acoustics; Akustik;

    Sammanfattning : This thesis contains three papers investigating problems of interest for noise control in ducts. The first part of this thesis treats the sound propagation in rectangular ducts with flexible walls. Various experimental techniques are performed to measure the internal sound propagation and radiation to the surrounding. LÄS MER

  3. 2. Reconfigurable Impedance Matching Networks for Radio Receivers

    Författare :Peter Sjöblom; Institutionen för elektro- och informationsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Telekommunikationsteknik; Telecommunication engineering; Elektronik; Electronics; reconfigurable matching; switched capacitor; antenna tuning unit; impedance tuning unit; High frequency technology; Elektroteknik; microwaves; Högfrekvensteknik; mikrovågor;

    Sammanfattning : Mobile phones become smaller but include more advanced functions for every new generation. This paradox is possible since reduced transistor size and increased integration of digital building blocks free space for new functions. LÄS MER

  4. 3. Application of the Boundary Element Method to combustion noise and half-space problems

    Författare :Haike Brick; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; impedance plane; Green s function; horn effect; Kirchhoff s surface; Hybrid approach; tyre-road interface;

    Sammanfattning : The Boundary-Element-Method (BEM) is a powerful and established tool in computational acoustics. This thesis aims at an enhancement of the method towards combustion noise and half-space problems.First, it is directly coupled to an incompressible Large Eddy Simulation (LES) to calculate the sound radiation of open flames. LÄS MER

  5. 4. Innovative noise control in ducts

    Författare :Maaz Farooqui; Mats Åbom; Hans Bodén; Tamer Elnady; Jeong-Guon Ih; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Locally resonant materials; slow sound; acoustic impedance; metallic foam; low frequency noise; mufflers; lined ducts; grazing flow; flow duct; impedance eduction.; Vehicle and Maritime Engineering; Farkostteknik;

    Sammanfattning : The objective of this doctoral thesis is to study three different innovative noise control techniques in ducts namely: acoustic metamaterials, porous absorbers and microperforates. There has been a lot of research done on all these three topics in the context of duct acoustics. LÄS MER

  7. 5. Scattering and propagation of electromagnetic waves in planar and curved periodic structures - applications to plane wave filters, plane wave absorbers and impedance surfaces

    Författare :Ola Forslund; KTH; []
    Nyckelord :electromagnetic scattering; periodic structure; frequency selectiove structure; frequency selective surface;

    Sammanfattning : The subject of this thesis is scattering of electromagneticwaves from planar and curved periodic structures. The problemspresented are solved in the frequency domain.Scattering from planar structures with two-dimensionalperiodic dependence of constitutive parameters is treated. LÄS MER