Sökning: "active antennas"

Visar resultat 21 - 25 av 41 avhandlingar innehållade orden active antennas.

1. 21. Antenna array systems : electromagnetic and signal processing aspects

   Författare :Maria Lanne; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : A simple and commonly used model of an array antenna consists of identical sensors, which are equidistantly located along a line. But in reality the array antennas do not look this way. The elements are not perfectly positioned, and sometimes they are even placed on a curved surface (conformal arrays). LÄS MER

3. 22. 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

4. 23. 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

5. 24. Signal Processing Aspects of Cell-Free Massive MIMO

   Författare :Giovanni Interdonato; Erik G. Larsson; Hien Quoc Ngo; Tommy Svensson; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The fifth generation of mobile communication systems (5G) promises unprecedented levels of connectivity and quality of service (QoS) to satisfy the incessant growth in the number of mobile smart devices and the huge increase in data demand. One of the primary ways 5G network technology will be accomplished is through network densification, namely increasing the number of antennas per site and deploying smaller and smaller cells. LÄS MER

7. 25. Embedded Element Patterns in Combination with Circuit Simulations for Multi-Port Antenna Analysis

   Författare :Kristian Karlsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; antenna efficiency; Greens function; multi-port antenna; impedance matching; reverberation chamber; correlation; antenna arrays; Embedded element pattern; optimization; antenna diversity;

   Sammanfattning : This thesis is a result from work on two different subjects, electromagnetic simulations of reverberation chambers and a methodology for the analysis of multi-port antennas. The subjects can be linked together by their contribution to knowledge in electromagnetic simulations and characterization of antennas. LÄS MER