Search for dissertations about: "high impedance surface"

Showing result 1 - 5 of 50 swedish dissertations containing the words high impedance surface.

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

   Author : Martin Löfgren; Chalmers University of Technology; []
   Keywords : 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;

   Abstract : 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. READ MORE

4. 2. Investigation of electrochemical properties and performance of stimulation/sensing electrodes for pacemaker applications

   Author : Anna Norlin; Jinshan Pan; Dieter Scharnweber; KTH; []
   Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; pacemaker electrode; interfacial property; biomaterial; electrostimulation charge transfer mechanism; electrochemical impedance spectroscopy; transient processes; plasma electrolysis anodisation; porous niobium oxide; ruthenium oxide; nano-porous carbon; iridium oxide; titanium nitride; platinum; surface roughness; porous electrode; pacing impedance; electrode polarisation; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi;

   Abstract : People suffering from certain types of arrhythmia may benefit from the implantation of a cardiac pacemaker. Pacemakers artificially stimulate the heart by applying short electrical pulses to the cardiac tissue to restore and maintain a steady heart rhythm. By adjusting the pulse delivery rate the heart is stimulated to beat at desired pace. READ MORE

5. 3. Nanofabrication of Single Electron Transistors and Evaluation of Miniature Biosensors

   Author : Linda G. M. Olofsson; Chalmers University of Technology; []
   Keywords : miniaturization; nanoparticles; impedance; single electron tunneling; biosensors; surface plasmon resonance;

   Abstract : This thesis deals with miniaturization in two different fields: electronics and biosensing. The first part deals with fabrication and measurements of two nanoscale structures - a self-assembled single electron transistor and a (potential) single junction device. READ MORE

6. 4. Ionic transport of α-alumina below 1000°C : an in-situ impedance spectrosocpy study

   Author : Johan Öijerholm; KTH; []
   Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Materials science; α-alumina; in-situ impedance spectroscopy; molecular dynamics; spark plasma sintering; conductivity; microstructure; Materialvetenskap; Materials science; Teknisk materialvetenskap;

   Abstract : Ionic conductivity of metal oxides is critical for the function of a broad range of different components, such as electrolytes in solid oxide fuel cells and alloys designed for high temperature applications. In both cases the ionic conductivity can be studied by in situ impedance spectroscopy, which is also able to reveal information on the dielectric properties of the metal oxides, and in some cases the influence of their microstructure. READ MORE

7. 5. Circuit Design Techniques for Implantable Closed-Loop Neural Interfaces

   Author : Nikola Ivanisevic; Ana Rusu; Saul Rodriguez; Angel Rodriguez Vazquez; KTH; []
   Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Neural interface; ECoG; high-resolution; ADC; recording; delta-sigma modulator; system identification; impedance measurements; Informations- och kommunikationsteknik; Information and Communication Technology;

   Abstract : Implantable neural interfaces are microelectronic systems, which have the potential to enable a wide range of applications, such as diagnosis and treatment of neurological disorders. These applications depend on neural interfaces to accurately record electrical activity from the surface of the brain, referred to as electrocorticography (ECoG), and provide controlled electrical stimulation as feedback. READ MORE