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Showing result 1 - 5 of 11 swedish dissertations matching the above criteria.

2. 1. Gap Waveguide for High Frequency Microwave Application- Validation of Concept, Filter Design & Packaging Aspects

   Author : Ashraf Uz Zaman; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; parallel plate stopband; PMC packaging; gap waveguide; fractional bandwidth; Quasi-TEM mode; PMC surface; narrowband filter; high Q resonators;

   Abstract : The overall goal of this thesis is to validate the low loss performance of recently evolved gap waveguide technology and to use this low loss technology for designing critical passive microwave component such as narrow band filter. Also, the exploitation of gap waveguide concept as a packaging solution for densely packed RF circuitry has been presented in this thesis. READ MORE

4. 2. Extending the Bandwidth of the Doherty Power Amplifier

   Author : David Gustafsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Abstract : The Doherty power amplifier (DPA) is one of the most popular power amplifier (PA) architectures used to obtain high efficiency for modern communication signals having high peak-to-average power ratios. Its often narrowband performance does, however, make it difficult for the DPA to meet the increasing demands of frequency agility in modern wireless communication systems. READ MORE

5. 3. Wideband THz Mixers and Components for the Next Generation of Receivers for Radioastronomy

   Author : Cristian Daniel López; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spectroscopy; Heterodyne receivers; Finline; Superconductor-Insulator-Superconductor SIS mixers.; Waveguide-to-Substrate Transition; Waveguide twist;

   Abstract : In recent decades, there has been a growing interest in THz research, leading to substantial improvements in technology and the emergence of new applications. In particular, the ever-evolving field of radio astronomy instrumentation has been pushing the limits of millimeter and sub-millimeter technology boundaries, redefining the state-of-the-art for wideband low-noise receivers. READ MORE

6. 4. Theory and Design of Wideband Doherty Power Amplifiers

   Author : David Gustafsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Doherty; gallium nitride; GaN; power amplifier; MMIC; microwave; Broadband amplifiers; high efficiency; wideband;

   Abstract : The Doherty power amplifier (DPA) is one of the most popular power amplifier architectures for obtaining high average efficiency for modern communication signals with high peak-to-average power ratios (PAPR). However, the DPA suffers from often having narrowband performance which limits its capabilities in wideband and/or multi-standard microwave and radio frequency applications. READ MORE

7. 5. THz Ultra-wideband Passive Devices: Design, Simulation and Characterization

   Author : Cristian Daniel López; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Superconducting Transition; Substrateless Finline; Compact waveguide twist; Marchand Baluns.; Broadband Waveguide to Substrate Transition;

   Abstract : The last decades have seen an increasing interest in the THz research field, leading to a substantial improvement in technology and the emergence of new applications. In particular, the research on radio astronomy instrumentation has pushed millimeter and sub-millimeter technology boundaries and redefined state of the art. READ MORE