Search for dissertations about: "High frequency antenna"

Showing result 1 - 5 of 136 swedish dissertations containing the words High frequency antenna.

2. 1. High Frequency Microwave and Antenna Devices based on Transformation Optics and Glide-Symmetric Metasurfaces

   Author : Mahsa Ebrahimpouri; Oscar Quevedo-Teruel; Nader Engheta; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Glide Symmetry; Transformation Optics; Lens Antennas; High Frequency; Microwave Devices; Electrical Engineering; Elektro- och systemteknik;

   Abstract : The new generation of wireless communication networks intends to support data rate of Gbit/s. One solution to make it possible is to move upwards in frequency range to employ the unused spectrum in mm-wave frequencies. READ MORE

4. 2. Antenna Integrated Superconducting Mixers

   Author : Hans Ekström; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; tapered slotline antenna; mixer; double dipole antenna; superconducting; hot electron; receiver; Niobium; bolometer; trilayer junction; edge junction; Niobium Nitride; SIS;

   Abstract : This thesis investigates the prospects of some different superconducting mixers integrated with planar antennas for the millimeter and submillimeter regime. Two kinds of Superconductor/Insulator/Superconductor (SIS) tunnel junctions for use in mixers have been fabricated; Nb/PbBi edge junctions and Nb trilayer junctions. READ MORE

5. 3. Fast Adaptive Numerical Methods for High Frequency Waves and Interface Tracking

   Author : Jelena Popovic; Olof Runborg; Hongkai Zhao; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; high frequency waves; Helmholtz equation; interface tracking; time-space adaptivity; multiresolution; Hamilton-Jacobi;

   Abstract : The main focus of this thesis is on fast numerical methods, where adaptivity is an important mechanism to lowering the methods' complexity. The application of the methods are in the areas of wireless communication, antenna design, radar signature computation, noise prediction, medical ultrasonography, crystal growth, flame propagation, wave propagation, seismology, geometrical optics and image processing. READ MORE

6. 4. Thick Frequency Selective Structures

   Author : Björn Widenberg; Institutionen för elektro- och informationsteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; acoustics; Elektromagnetism; optik; akustik; optics; Electromagnetism; Energy Saving Window; Radome; Finite Elemente Method; Frequency Selective Structure; Mode Matching Technique;

   Abstract : This thesis presents a new method that can handle a general thick Frequency Selective Structure (FSS), that consists of an arbitrary number of aperture layers and dielectric layers. The method is based on the Mode Matching Technique (MMT) and the finite element method (FEM). The thesis consists of a General Introduction and five scientific papers. READ MORE

7. 5. Optimizing microwave hyperthermia antenna systems

   Author : Pegah Takook; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; head and neck tumors.; wideband antenna; microwave hyperthermia; time reversal;

   Abstract : This thesis presents design and optimization of a microwave hyperthermia antenna system for treatment of head and neck cancer as well as brain cancer. Hyperthermia has shown the ability to enhance the performance of radiotherapy and chemotherapy in many clinical trials. READ MORE