Search for dissertations about: "varactor"

Showing result 1 - 5 of 32 swedish dissertations containing the word varactor.

  1. 1. Symmetric varactor frequency multipliers

    Author : Mattias Ingvarson; Chalmers University of Technology; []
    Keywords : sub-millimetre wave; heterostructure barrier varactor HBV ; symmetric varactor; frequency multiplier; millimetre wave; semiconductor diode;

    Abstract : This thesis describes heterostructure barrier varactor (HBV) frequency multipliers for millimetre and sub-millimetre wave applications.The basic principles of HBVs are explained. Starting from basic varactor theory, an equivalent circuit model for HBVs is presented. READ MORE

  2. 2. Integrated VCOs in Gallium Arsenide HEMT technologies with a novel varactor structure

    Author : Mattias Ferndahl; Chalmers University of Technology; []

    Abstract : This thesis presents results on metamorphic and pseudomorpic GaAs HEMT based Voltage Controlled Oscillators and a novel high-Q varactor structure, used in the VCOs, together with a straightforward extraction procedure for the varactors.Theory and fundamentals around LC-oscillators with oscillator criteria, phase noise and different topologies are given as background together with VCO phase noise measurement methods and an overview on device flicker noise; its physical origin and measurement. READ MORE

  3. 3. Frequency Reconfigurable and Linear Power Amplifiers Based on Doherty and Varactor Load Modulation Techniques

    Author : William Hallberg; Chalmers University of Technology; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; gallium nitride GaN ; wideband; Class-J; linear; microwave; radio frequency RF ; Doherty; broadband; AM AM; silicon carbide SiC ; bandwidth; power amplifier PA ; AM PM; varactor; dynamic load modulation DLM ; fifth generation mobile networks 5G ; energy efficiency;

    Abstract : In future mobile communication networks, there will be a shift towards higher carrier frequencies and highly integrated multiple antenna systems. The system performance will largely depend on the available RF hardware. As such, RF power amplifiers (PAs) with improved efficiency, linearity, and bandwidth are needed. READ MORE

  4. 4. Planar Heterostructure Barrier Varactor Diodes for Millimetre Wave Applications

    Author : Jan Stake; Chalmers University of Technology; []
    Keywords : millimetre- and sub-millimetre wave power source; III-V semiconductor; varactor diode; frequency multiplier; Heterostructure Barrier Varactor HBV ;

    Abstract : This thesis deals with fabrication, characterisation and modelling of the Heterostructure Barrier Varactor (HBV) diode and its use in frequency multiplier applications. Different aspects of material structures and frequency multipliers are described. READ MORE

  5. 5. Characterization of (Ba,Sr)TiO3 thin films for multiplier applications

    Author : Pär Rundqvist; Chalmers University of Technology; []
    Keywords : NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; BSTO; THz; triplers; powerhandling capability; multilayer structures; frequency multipliers; Ferroelectric; BST; losses; Varactor; STO;

    Abstract : (Ba,Sr)TiO3 (BSTO) and SrTiO3 (STO) parallel plate ferroelectric varactors are investigated for microwave multiplier applications.STO and BSTO exhibit low losses, high permittivity and largetunability of both permittivity and losses. All films are deposited using Pulsed Laser Deposition, magnetron sputtering and E-beam evaporation. READ MORE