Sökning: "Small antennas"

Visar resultat 1 - 5 av 91 avhandlingar innehållade orden Small antennas.

  1. 1. Integrated Antennas : Monolithic and Hybrid Approaches

    Författare :Erik Öjefors; Anders Rydberg; Sayan Mukherjee; Duixian Liu; Uppsala universitet; []
    Nyckelord :Electronics; antenna travelling wave arrays; antenna phased arrays; phase shifters; micromachining; silicon; monolithic microwave integrated circuits; dipole antennas; loop antennas; slot antennas; Elektronik;

    Sammanfattning : This thesis considers integration of antennas and active electronics manufactured on the same substrate. The main topic is on-chip antennas for commercial silicon processes, but hybrid integration using printed circuit board technology is also addressed. LÄS MER

  3. 2. Limitations on efficiency, size and bandwidth of small antennas

    Författare :Daniel Nyberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; log-periodic antennas; Small antennas; folded dipoles; radiation Q; fundamental limitations; bandwidth;

    Sammanfattning : The allocated space in a mobile phone for the antennas has become smaller and smaller following the size reduction of the mobile phones themselves and the integration of more functions in them. At the same time new communication systems are being planned where such small antennas also need to be wideband (UWB systems) or have multiple ports (MIMO systems). LÄS MER

  4. 3. Predictor Antennas : Enabling channel prediction for fast-moving vehicles in wireless broadband systems

    Författare :Joachim Björsell; Mikael Sternad; Anders Ahlén; Fredrik Tufvesson; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Predictor antenna; Channel prediction; Long-range prediction; Massive MIMO; Spline interpolation; Channel aging; Outdated CSI; Electrical Engineering with specialization in Signal Processing; Elektroteknik med inriktning mot signalbehandling;

    Sammanfattning : Many advanced transmission techniques utilize channel state information (CSI) at the transmitter (CSIT) to improve throughput, spectral efficiency, power efficiency, and other performance metrics. Estimating CSI accurately is important to fully benefit from many of these techniques. LÄS MER

  5. 4. Dielectrically Loaded Quad-ridge Flared Horns for Ultra Wideband Reflector Feed Applications in Radio Astronomy

    Författare :Jonas Flygare; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric loaded antennas; dielectric materials; reflector antenna feeds; radio astronomy; ultra wideband antennas; quad-ridge flared horn qrfh ; radio receivers; horn antennas; broadband antennas; aperture antennas.;

    Sammanfattning : Reflector-based radio telescopes are used as tools for observations in both radio astronomy and space geodesy. To observe the weak sources in space, highly sensitive receivers, fronted by optimized reflector feeds, are therefore needed. LÄS MER

  7. 5. Integrated Antenna Solutions for Wireless Sensor and Millimeter-Wave Systems

    Författare :Shi Cheng; Anders Rydberg; Paul Hallbjörner; Zhining Chen; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; harmonic radar HR ; liquid alloy; millimeter-wave; micromachining; phase shifters; planar inverted cone antennas PICA ; printed circuit boards PCB ; quasi-Yagi antennas; radio frequency microelectromechanical system RF MEMS ; stretchable antennas; substrate integrate waveguides SIW ; T-matched dipole antennas; tapered slot antennas; traveling wave array antennas; ultrawideband UWB ; wireless sensor networks.; Electrical engineering; Elektroteknik; Elektronik; Electronics;

    Sammanfattning : This thesis presents various integrated antenna solutions for different types of systems and applications, e.g. wireless sensors, broadband handsets, advanced base stations, MEMS-based reconfigurable front-ends, automotive anti-collision radars, and large area electronics. LÄS MER