Sökning: "optical antennas"

Visar resultat 1 - 5 av 24 avhandlingar innehållade orden optical antennas.

  1. 1. Photonic terahertz-wave generation, radiation and quasioptical integration

    Författare :Biddut Kumar Banik; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; semiconductor device modelling; semiconductor diodes; III-V semiconductors; Catadioptric lens; imaging; dipole antennas; slot antennas; lens antennas; semiconductor heterojunctions; dielectric loaded antennas; optical mixers; photomixers; near-field imaging; computer aided engineering; indium compounds; millimetre wave imaging; near-field optics; submillimeter wave generation; photodiodes; terahertz sources; millimetre wave generation; submillimetre wave integrated circuits; microwave imaging; uni-travelling-carrier photodiodes;

    Sammanfattning : This thesis deals with the uni-travelling-carrier photodiode (UTC-PD) based photonic generation of terahertz waves, antenna designs for the terahertz radiation and a novelcatadioptric lens for quasioptical integration.The ongoing and accomplished research work on the UTC-PD, its limitations and optimisation scopes for attaining higher bandwidth and higher output power have been discussed. LÄS MER

  2. 2. Optical Analysis and Characterisation of the Climate Research Instrument STEAMR

    Författare :Arvid Hammar; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; limb viewing; Monte Carlo; Stratosphere-Troposphere Exchange And climate Monitor Radiometer STEAMR ; quasi optics; THz; antennas; multi-beam; tolerance analysis; submillimeter-wave instruments; radiometers;

    Sammanfattning : A growing interest for making high resolution observations in the upper troposphere and lower stratosphere has motivated the development of the multi-beam satellite-borne instrument Stratosphere-Troposphere Exchange And climate Monitor Radiometer (STEAMR). The measurements made by STEAMR will be used to monitor trace-gases and link the occurence of these to the Earth's climate by accurate modeling of the atmosphere. LÄS MER

  3. 3. Effects of surface plasmons in subwavelength metallic structures

    Författare :Srinivasan Iyer; Ari T. Friberg; N. Asger Mortensen; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; suface plasmons; extraordinary transmission; metamaterials; shnets; split-ring resonators; plasmon-induced EIT; optical antennas; plasmonics;

    Sammanfattning : The study of optical phenomena related to the strong electromagnetic response of noble metals (silver (Ag) and gold (Au) being most popular) over the last couple of decades has led to the emergence of a fast growing research area called plasmonics named after 'surface plasmons' which are electron density waves that propagate along the interface of a metal and a dielectric medium. Surface plasmons are formed by the coupling of light to the electrons on the metal surface subject to the fulfillment of certain physical conditions and they are bound to the metal surface. LÄS MER

  4. 4. Integration of Planar Antennas with MMIC Active Frontends for THz Imaging Applications

    Författare :Yogesh Karandikar; Chalmers University of Technology; []
    Nyckelord :Sub-Harmonic Resistive Mixer; Planar Antennas; Gaussian Coupling; MMIC; Gilbert Cell Mixer; THz;

    Sammanfattning : In recent years, there has been constant growth in using THz frequencies or mm, sub- mm wavelengths for various applications such as: Astronomy, Atmospheric studies, security, bio-medical imaging. All these applications are now seen more feasible due to rapid enhancements of semi-conductor processing technologies. LÄS MER

  5. 5. Photonic THz Generation and Quasioptical Integration for Imaging Applications

    Författare :Biddut Kumar Banik; Chalmers University of Technology; []
    Nyckelord :nondestructive evaluation; semiconductor device modelling; uni-travelling-carrier photodiodes; millimetre wave and submillimetre wave generation; III-V semiconductors; photomixers; terahertz sources.; catadioptric lens; microwave imaging; dielectric loaded antennas; terahertz imaging; lens antennas; millimetre wave and submillimetre wave imaging;

    Sammanfattning : This thesis deals with the analysis and optimisation of the uni-travelling-carrier photodiode (UTC-PD) for continuous-wave generation in terahertz (THz) frequencyrange. Photonic THz generation using UTC-PDs is extremely promising as it offers wide tunability, adequate output power and room temperature operation. LÄS MER