Sökning: "beam steering"

Visar resultat 1 - 5 av 28 avhandlingar innehållade orden beam steering.

1. 1. Nonlinear Beam Physics

   Författare :Benjamin Folsom; Partikel- och kärnfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; nonlinear dynamics; Beam dynamics; Accelerator Physics; space charge; Accelerator magnets; simulations multi-particle dynamics;

   Sammanfattning : A condensed treatment of conventional beam physics (both linear and nonlinear) is given for the non-expert; this constitutes a minimum knowhow for constructing simulations of rudimentary beamlines. The criteria for an ideal nonlinear charged-particle simulation algorithm are then presented, leading to the derivation of a symplectic, explicit, Lorentz-covariant integrator. LÄS MER

3. 2. Nematic Liquid Crystal Spatial Light Modulators for Laser Beam Steering

   Författare :Emil Hällstig; Mikael Lindgren; Lars Sjöqvist; William Crossland; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; spatial light modulator; liquid crystal; beam steering; tracking; phase modulation; fringing field; director distribution; finite-difference time-domain; polarization; temporal properties; Fysik; Physics; Fysik;

   Sammanfattning : Laser beam control is important in many applications. Phase modulating spatial light modulators (SLMs) can be used to electronically alter the phase distribution of an optical wave-front and thus change the direction and shape of a laser beam. LÄS MER

4. 3. Active Transmitter Antenna Array Modeling for MIMO Applications

   Författare :Parastoo Taghikhani; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; beam steering; Active antenna array; active impedance; hybrid beamforming transmitter; MIMO transmitter; far-field nonlinear distortion; millimeter wave; modeling.;

   Sammanfattning : The rapid growth of data traffic in mobile communications has attracted interests to the Multiple-Input-Multiple-Output (MIMO) communication systems at millimeter-wave (mmWave) frequencies.  MIMO systems exploit active transmitter antenna arrays for higher energy efficiency and providing beamforming flexibility. LÄS MER

5. 4. Multi-Level Lossless Phase Modulation in Liquid Crystals for High-Speed Spatial Light Modulators

   Författare :David Engström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; phase measurements; polarization; phase modulation; beam steering; Spatial light modulators; diffractive optics; ferroelectric liquid crystals;

   Sammanfattning : The spatial light modulator (SLM) is a compact device that enables highly precise control of light propagation with low drive voltages and no moving parts. By imposing a certain phase modulation onto the incident lightwave, functions such as multi-beam steering, beam shaping, and air turbulence corrections can be achieved in realtime. LÄS MER

7. 5. On millimeter and submillimeter wave focal plane arrays implemented with MEMS waveguide switches

   Författare :Henrik Frid; Joachim Oberhammer; Vessen Vassilev; Mikro- och nanosystemteknik KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Extended Hemispherical Lens; Beam Steering; Focal Plane Array FPA ; Ray-Tracing; RF MEMS; waveguide switch; micromachined waveguide; submillimeter-wave; rectangular waveguide; terahertz; lenses; antenna theory; silicon; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis presents research towards enabling micromachined millimeter and submillimeter wave focal plane arrays (FPAs). The FPAs operate under the following principle: a switch network consisting of microelectromechanical (MEMS) switches, integrated with micromachined waveguides, is used to feed an array of antenna elements, located in the focal plane of a high-gain quasi-optical system. LÄS MER