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Showing result 1 - 5 of 13 swedish dissertations matching the above criteria.

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

   Author : Biddut Kumar Banik; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 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;

   Abstract : 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. READ MORE

4. 2. Single layer near-field acoustic imaging in space-invariant reflective environments

   Author : Elias Zea; Ines Lopez Arteaga; Efren Fernandez-Grande; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; near-field acoustic holography; field separation techniques; single layer; space-invariance; reflective envirionments; närfält akustisk holografi; fältseparationstekniker; enkelt lager; utrymmes invarians; reflekterande miljöer; Vehicle and Maritime Engineering; Farkostteknik;

   Abstract : The visualization of optical fields, or widely known as photography, is a common practice that can also be applied to acoustic fields. No less than three decades of research in acoustic imaging demonstrate its potential and relevance in plenty applications such as sound source identification and localization, as well as characterization of noise generation mechanisms. READ MORE

5. 3. Measurement and evaluation of near-field spray kinematics for nozzles with asymmetrical inlet geometries

   Author : Mohammad Nikouei; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nozzle Geometry; Spray Dynamics; Spray Velocity; Diesel Spray; Ballistic Imaging;

   Abstract : In diesel engines, fuel injection parameters have a commanding effect on mixing and combustion quality. This research aims to enhance the fundamental knowledge of fuel sprays and their primary break-up. In addition, this research provides statistical data to validate simulation models and improve the prediction accuracy in mixing and combustion. READ MORE

6. 4. Optical Imaging and Spectroscopy of Metal Nanostructures

   Author : Juris Prikulis; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; nanoparticles; surface plasmon resonance; surface-enhanced Raman spectroscopy; near-field optical microscopy; optical tweezers;

   Abstract : Noble metal structures with size in the sub 100 nm range exhibit extraordinary optical properties due to collective oscillations of conduction electrons, the surface plasmon resonances (SPR). The most remarkable feature of these structures is the ability to redistribute electromagnetic radiation and concentrate strong fields near the surface. READ MORE

7. 5. Design of Functional Structures and Measurement Techniques for Electromagnetic Waves

   Author : Johan Lundgren; Teoretisk elektroteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; functional structures; frequency selective structures; polarization selectivity; metasurface; near-field measurements; antenna measurements; scattering measurement; power density; random media;

   Abstract : Electromagnetic fields exist all around us. Through evolution, nature has developed tools to interact and use these fields, where our eyes are a spectacular example. Humans have a long history of developing structures and objects of their own to alter and interact with these fields. READ MORE