Sökning: "microwave surface resistance"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden microwave surface resistance.

  1. 1. Device Technology Based on High Temperature Superconductors and Microwave Breakdown in Gases

    Författare :Martin Löfgren; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; distortion; penetration depth; surface resistance; transmit-receive switch; coupled-grain model; high-power; microwave; pulse; surface impedance; breakdown; propagation; modulator; air; superconductor; transmission line; resonator; coplanar waveguide; plasma;

    Sammanfattning : This thesis deals with two separate fields of microwave technology. The first section treats microwave characterization and applications of high temperature superconducting (HTS) thin films, while the second section treats microwave breakdown in transmit-receive (TR) switches and in air. Within the first section, four main topics are adressed. LÄS MER

  3. 2. Methods for Characterization and Optimization of AlGaN/GaN HEMT Surface Passivation

    Författare :Martin Fagerlind; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; surface states; surface passivation; annealing; processing; AlGaN GaN HEMT; MIS-capacitor;

    Sammanfattning : The Gallium Nitride based high electron mobility transistor is rapidly improving and is emerging as a viable alternative for use in high power applications operating in the microwave frequency domain. The suitability of the AlGaN/GaN material system is due to the possibility to grow epitaxial heterostructures that provide; high electron mobility, high electron saturation velocity, high carrier density and a high dielectric breakdown field. LÄS MER

  4. 3. Cellulose derived carbon dots : From synthesis to evaluation as multifunctional building blocks in biomedical scaffolds

    Författare :Nejla Benyahia Erdal; Minna Hakkarainen; Jukka Seppälä; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; cellulose; microwave; carbon dots; polycaprolactone; scaffold; mineralization; drug loading; cellulosa; mikrovågor; kolnanopartiklar; polykaprolakton; stödmatris för vävnadsregenerering; mineralisering; läkemedelsbärare; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : The implementation of biobased and biodegradable polymeric materials in biomedical applications is often coupled with issues related to their insufficient mechanical properties or limited bioactivity. In this thesis, a perspective on valorization of biomass is presented, demonstrating the transformation of cellulose into biobased carbon nanomaterials with the potential to serve as multifunctional property enhancers in polycaprolactone (PCL) scaffold materials for tissue engineering. LÄS MER

  5. 4. Graphene field-effect transistors for high frequency applications

    Författare :Muhammad Asad; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; high frequency; Graphene; transit frequency; transconductance; maximum frequency of oscillation; contact resistance; microwave electronics; field-effect transistors;

    Sammanfattning : Rapid development of wireless and internet communications requires development of new generation high frequency electronics based on new device concepts and new materials. The very high intrinsic velocity of charge carriers in graphene makes it promising new channel material for high frequency electronics. LÄS MER

  7. 5. Laser deposited thin films of the high temperature superconductors YBaCuO and BiSrCaCuO

    Författare :Göran Brorsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MgO; BiSrCaCuO; Y-ZrO2< sub>; laser deposition; thin films; microwave surface resistance; morphology; YBaCuO;

    Sammanfattning : .... LÄS MER