Sökning: "Pulse Wave Imaging"

Visar resultat 6 - 10 av 21 avhandlingar innehållade orden Pulse Wave Imaging.

1. 6. Compact and Efficient Millimetre-Wave Circuits for Wideband Applications

   Författare :Lars Ohlsson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; resonant-tunnelling diode; millimetre-wave spectrum; integrated transmitter; energy-efficiency; compact circuit; dielectric resonator antenna; transistor; wavelet generator; wideband.;

   Sammanfattning : Radio systems, along with the ever increasing processing power provided by computer technology, have altered many aspects of our society over the last century. Various gadgets and integrated electronics are found everywhere nowadays; many of these were science-fiction only a few decades ago. LÄS MER

3. 7. Electron Tunneling and Field-Effect Devices in mm-Wave Circuits

   Författare :Mikael Egard; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; negative differential conductance oscillator; resonant tunneling diode; ultra-wideband; impulse radio; Wavelet generator; MOSFET; nanowire; high frequency characterization; Fysicumarkivet A:2012:Egard;

   Sammanfattning : Short high-frequency electromagnetic pulses, also referred to as wavelets, are considered for use in various short-range impulse based ultra-wideband applications, such as communication, imaging, radar, spectroscopy, and localization. This thesis investigates field-effect and tunneling based semiconductor devices and their operation in millimeter-wave (mm-wave) impulse transceivers. LÄS MER

4. 8. Time-Domain Antenna and Scattering Analysis for Micro- and Millimeter-Wave Applications

   Författare :Iman Vakili; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Telecommunications industries are investing tremendously to meet the ever-increasing demands for higher data rates and capacity. In particular to develop standardization for 5G, which is expected around 2020. The existing spectrum for traditional mobile networks is limited to highly occupied bands at microwave frequencies below 6 GHz. LÄS MER

5. 9. Development and Applications of a Laser-Wakefield X-ray Source (updated)

   Författare :Isabel Gallardo Gonzalez; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; laser-wakefield acceleration; betatron radiation; ionization-induced trapping; direct laser acceleration; laser-wakefield merging; warm dense matter; phase-contract imaging;

   Sammanfattning : In laser-wakefield acceleration (LWFA), a femtosecond laser pulse is tightly focused in a gas to intensities exceeding 1018 W/cm2 . The laser radiation ionizes the medium and excites a plasma wave that travels behind the laser pulse. LÄS MER

7. 10. Short Attosecond Pulse Trains at High Repetition Rates for Novel Pump-Probe and Coincidence Studies

   Författare :Sara Mikaelsson; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Attosecond; High-Order Harmonic Generation; Photoionization; Attosecond; High-Order Harmonic Generation; Photoionization; Fysicumarkivet A:2021:Mikaelsson;

   Sammanfattning : This work aims at studying photoionization dynamics from atoms and surfaces at attose time scales. The work was based on development and applications of a high repetition rate High-order Harmonic Generation (HHG) light source that utilizes Optical Parametric Amplification (OPA) laser technology. LÄS MER