Search for dissertations about: "rf and antenna"

Showing result 1 - 5 of 50 swedish dissertations containing the words rf and antenna.

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

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

    Abstract : 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. READ MORE

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

    Author : Katharina Hausmair; Chalmers University of Technology; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; multi-antenna transmitter; behavioral modeling; over-the-air characterization; digital predistortion; antenna crosstalk; linearization; power amplifier;

    Abstract : 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. READ MORE

  3. 3. Phased-Array-Fed Reflector Antenna Systems for Radio Astronomy and Earth Observations

    Author : Oleg Iupikov; Chalmers University of Technology; []
    Keywords : TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY;

    Abstract : Dense Phased Array Feeds (PAFs) for reflector antennas have numerous advantages over traditional cluster feeds of horns in a one-horn-per-beam configuration, especially in RF-imaging applications which require multiple simultaneously formed and closely overlapped beams. However, the accurate analysis and design of such PAF systems represents a challenging problem, both from an EM-modeling and beamforming optimization point of view. READ MORE

  4. 4. Selected Applications of Switched Capacitor Circuits : RF N-Path Filters and ΣΔ Modulators

    Author : Fahad Qazi; Jerzy Dabrowski; Atila Alvandpour; Henrik Sjöland; Linköpings universitet; []
    Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER;

    Abstract : Electronic circuits based on switches and capacitors have been used in various applications for several decades. The common switched capacitor (SC) circuits have made their career primarily in analog filters and data converters due to high immunity to capacitance mismatch in integrated circuit (IC) technologies. READ MORE

  5. 5. Ultra-wideband Millimeter-wave Antenna Arrays and Front-end Systems : For high data rate 5G and high energy physics applications

    Author : Imran Aziz; Dragos Dancila; Ville Viikari; Uppsala universitet; []
    Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : The demand for wireless data communications is rapidly increasing due to several factors including increased internet access, increasingly growing number of mobile users and services, implementation of the Internet of Things (IoT), high-definition (HD) video streaming and video calling. To meet the bandwidth requirement of new and emerging applications, it is necessary to move from the existing microwave bands towards millimeter-wave bands. READ MORE