Sökning: "antenna arrays"

Visar resultat 11 - 15 av 81 avhandlingar innehållade orden antenna arrays.

  1. 11. Active and Passive Unequally Spaced Reflect-Arrays and Elements of RF Integration Techniques

    Författare :Dhanesh G. Kurup; Anders Rydberg; Mohamed Himdi; Peter S Hall; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Active Antenna; Reflect-arrays; NRD guide; RF integration; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : Using an array synthesis tool based on a modified differential evolution algorithm, it is shown that the position-phase synthesis exhibits improved pattern characteristics compared to both the phase only and position only synthesis of uniform amplitude antenna arrays. The design of an unequally spaced planar reflect-array and an active power combining reflect-array are presented. LÄS MER

  3. 12. Direction finding, beamforming and mutual coupling in base station antenna arrays

    Författare :Staffan Lundgren; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; mutual coupling; adaptive arrays; direction finding; base station antennas; mobile communications; phase-only nulling; beamforming; dual polarization; butler matrix;

    Sammanfattning : .... LÄS MER

  4. 13. Radiation and Scattering from Conformal Array Antennas

    Författare :Björn Thors; KTH; []
    Nyckelord :conformal antennas; antenna arrays; antenna radiation patterns; radar cross sections; electromagnetic scattering; UTD; moment methods; high frequency method; hybrid method; mutual coupling;

    Sammanfattning : This thesis deals with radiation and scattering fromconformal array antennas. A hybrid technique between the Methodof Moments (MoM) and different asymptotic methods is used forthe analysis, combining the accuracy of the MoM and theefficiency of the asymptotic methods. LÄS MER

  5. 14. Modeling and Compensation of Nonlinear Distortion in Multi-Antenna RF Transmitters

    Författare :Katharina Hausmair; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; multi-antenna transmitter; behavioral modeling; over-the-air characterization; digital predistortion; antenna crosstalk; linearization; power amplifier;

    Sammanfattning : Multi-antenna systems are utilized as a way to increase spectral efficiency in wireless communications. In a transmitter, the use of several parallel transmit paths and antennas increases system complexity and cost. Cost-efficient solutions, which employ active antenna arrays and avoid expensive isolators, are therefore preferred. LÄS MER

  7. 15. Faceted conformal antenna arrays analyzed with the uniform theory of diffraction

    Författare :Carina Marcus; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Faceted Conformal Antenna; High-frequency methods; Ray tracing;

    Sammanfattning : Faceted conformal antenna arrays are analyzed with the uniform theory of diffraction (UTD). Parameters such as mutual coupling, scattering parameters, isolated and embedded element patterns are calculated.A ray tracing algorithm for handling rays on a faceted surface, which is needed for the UTD calculations, is also described.. LÄS MER