Sökning: "Antenna Array"

Visar resultat 6 - 10 av 150 avhandlingar innehållade orden Antenna Array.

  1. 6. 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

  3. 7. Modeling of a Retrodirective Channel With Active Antenna Arrays for Cross-Eye Jamming

    Författare :Björn Petersson; Martin Norgren; Warren P. du Plessis; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electronic warfare; antenna array; antenna system; radar countermeasures; jamming; cross-eye; systems modeling; system performance; systems simulation; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Cross-Eye (CE) jamming is a technique aimed at inducing false target angles in radar measurements. The potential to deceive monopulse radar, a radar type commonly used due to its angular accuracy and resilience against jamming, has captured the interest of Electronic Warfare (EW) system manufacturers. LÄS MER

  4. 8. Towards Gap Waveguide Array Antenna for Millimeter Wave Applications

    Författare :Abbas Vosoogh; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; gap waveguide; Electric Discharge Machining EDM ; Artificial Magnetic Conductor AMC ; slot array antenna; low sidelobe; high effciency; millimeter wave; aperture efficiency; Bandpass filter BPF ;

    Sammanfattning : The millimeter wave frequency range has got a lot of attention over the past few years because it contains unused frequency spectrum resources that are suitable for delivering Gbit/s end-user access in areas with high user density. Due to the limited output power that current RF active components can deliver in millimeter waves, antennas with the merits of low profile, high gain, high effciency and low cost are needed to compensate free space path loss and increase the communication distance for the emerging high data rate wireless systems. LÄS MER

  5. 9. Weighted Regression with Application to Array Antennas

    Författare :Astrid Lundgren; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; array antenna; weighted regression; statistical estimation theory; modelling; calibration;

    Sammanfattning : A nonlinear system can be modelled with a simple linear model ifthe model is only valid locally. This can be done by assigningweights to the estimation data, as a function of the distance tothe modelled point. The weighting is here used to develop adirection-dependent calibration method for array antennas. LÄS MER

  7. 10. On MIMO Systems and Adaptive Arrays for Wireless Communication : Analysis and Practical Aspects

    Författare :Mattias Wennström; Michael A. Jensen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systemteknik; antenna array; calibration; MIMO system; flat fading; non-linear amplifier; switched parasitic antenna; analog beamformer; adaptive antenna testbed; Systemteknik; Systems engineering; Systemteknik; Signal Processing; signalbehandling;

    Sammanfattning : This thesis is concerned with the use of multiple antenna elements in wireless communication over frequency non-selective radio channels. Both measurement results and theoretical analysis are presented. New transmit strategies are derived and compared to existing transmit strategies, such as beamforming and space-time block coding (STBC). LÄS MER