Sökning: "Sailing He"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden Sailing He.

  1. 1. Propagation of some coherent and partially coherent laser beams

    Författare :Yangjian Cai; Sailing He; Franco Gori; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; : dark hollow beam; elliptical Gaussian beam; flat-topped beam; twisted anisotropic Gaussian Schell-model; partial coherent; propagation; paraxial optical system; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : In this thesis, we investigate the propagation of some coherent and partially coherent laser beams, including a dark hollow beam (DHB), an elliptical Gaussian beam (EGB), a flat-topped beam and a twisted anisotropic Gaussian Schell-model (TAGSM) beam, through a paraxial optical system or a turbulent atmosphere. Several theoretical models are proposed to describe a DHB of circular or non-circular symmetry. LÄS MER

  2. 2. Designs and simulations of silicon-based microphotonic devices

    Författare :Daoxin Dai; Sailing He; Siegfried Janz; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electronics; waveguide; silicon-on-insulator SOI ; arrayed waveguide grating AWG ; Elektronik; Electronics; Elektronik;

    Sammanfattning : The characteristics of a silicon-on-insulator (SOI) rib waveguide, including the bending loss of a multimode bent waveguide and the birefringence of a rib waveguide, are analyzed by using a finite-difference method (FDM). Based on a detailed analysis for a multimode bent waveguide, an appropriately designed multimode bent waveguide for reducing effectively the bending loss of the fundamental mode is realized. LÄS MER

  3. 3. Some studies on metamaterial transmission lines and their applications

    Författare :Xin Hu; Sailing He; Ferran Martin; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; metamaterial; transmission line theory; composite right left-handed transmission line; diplexer; coupler; balun; interdigital capacitor; split ring resonator; Electrical engineering; Elektroteknik;

    Sammanfattning : This thesis focuses mostly on investigating different potential applications of meta-transmission line (TL), particularly composite right/left handed (CRLH) TL, and analyzing some new phenomena and applications of meta-TL, mostly left-handed (LH) TL. Realization principle will also be studied. LÄS MER

  4. 4. Decoupling and Evaluation of Multiple Antenna Systems in Compact MIMO Terminals

    Författare :Hui Li; Sailing He; Cyril Luxey; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multiple antennas; mutual coupling; compact antennas; frequency reconfigurable antennas; pattern reconfigurable antennas; meta-material antennas; mobile antennas; fractal antennas; collocated antennas; antenna measurement.;

    Sammanfattning : Research on multiple antenna systems has been a hot topic in recent years due to the demands for higher transmission rate and more reliable link in rich scattering environment in wireless communications. Using multiple antennas at both the transmitter side and the receiver side increases the channel capacity without additional frequency spectrum and transmitted power. LÄS MER

  5. 5. Imaging for subwavelength information with layered metamaterials

    Författare :Xuan Li; Sailing He; Thomas Taubner; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik;

    Sammanfattning : .... LÄS MER