Sökning: "radio frequency RF"

Visar resultat 11 - 15 av 156 avhandlingar innehållade orden radio frequency RF.

1. 11. Novel RF MEMS Devices Enabled by Three-Dimensional Micromachining

   Författare :Umer Shah; Joachim Oberhammer; Raafat Mansour; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Microelectromechanical systems; MEMS; Radio frequency microelectromechanical systems; RF MEMS; Micromachined transmission line; Micromachining; Tuneable capacitor; Switched capacitor; Coupled-line coupler; Tuneable directional coupler; Intermodulation distortion; MEMS varactor; Two-tone IIP3 measurement; Passive components and circuits; Reliability; Magnetic materials; NiFe multilayer composite; Permeability; Permittivity; Micromachined inductors;

   Sammanfattning : This thesis presents novel radio frequency microelectromechanical (RF MEMS) circuits based on the three-dimensional (3-D) micromachined coplanar transmission lines whose geometry is re-configured by integrated microelectromechanical actuators. Two types of novel RF MEMS devices are proposed. LÄS MER

3. 12. Nanowire Transistors and RF Circuits for Low-Power Applications

   Författare :Karl-Magnus Persson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :InAs; Nanowire; Metal-oxide-semiconductor field-effect transistor; MOSFET; RF; Mixer; Circuit; 1 f-noise; Simulation; Modelling;

   Sammanfattning : The background of this thesis is related to the steadily increasing demand of higher bandwidth and lower power consumption for transmitting data. The work aims at demonstrating how new types of structures, at the nanoscale, combined with what is referred to as exotic materials, can help benefit in electronics by lowering the consumed power, possibly by an order of magnitude, compared to the industry standard, silicon (Si), used today. LÄS MER

4. 13. Towards Ultimate Performance of THz Heterodyne Receivers: SIS Frequency Multiplier and Wideband Passive Components

   Författare :Hawal Marouf Rashid; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Wideband passive components; distributed SIS junction; Frequency multiplier; Frequency up-converter; Hybrids; distributed SIS frequency multiplier;

   Sammanfattning : This thesis focuses on the development of advanced components for the future wideband side band separating and / or multipixel receivers for radio-astronomy with ultimate sensitivity.In this thesis, a novel frequency multiplier based on distributed superconducting tunnel (SIS) junctions has been demonstrated for the first time, taking advantage of the extreme inherent nonlinearity of such device. LÄS MER

5. 14. Impact of Tissue Characteristics on Radio-Frequency Lesioning and Navigation in the Brain : Simulation, experimental and clinical studies

   Författare :Johannes Johansson; Karin Wårdell; Hans von Holst; Linköpings universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Brain; Radio frequency ablation; Finite element method; Monte Carlo simulation; light reflectance; Radiological research; Radiologisk forskning;

   Sammanfattning : Radio-Frequency (RF) lesioning, or RF ablation, is a method that uses high frequency currents for thermal coagulation of pathological tissue or signal pathways. The current is delivered from an electrode, which also contains a temperature sensor permitting control of the current at a desired target temperature. In the brain, RF lesioning can e.g. LÄS MER

7. 15. Studies on Selected Topics in Radio Frequency Digital-to-Analog Converters

   Författare :Mohammad Reza Sadeghifar; Jacob Wikner; Adam Strak; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; DAC; Telecommunication; Semi-digital FIR filter; RF DAC; Sigma Delta Modulator; DDFS;

   Sammanfattning : The network latency in fifth generation mobile technology (5G) will be around one millisecond which is much lower than in 4G technology. This significantly faster response time together with higher information capacity and ultra-reliable communication in 5G technology will pave the way for future innovations in a smart and connected society. LÄS MER