Sökning: "antenna array"

Visar resultat 26 - 30 av 150 avhandlingar innehållade orden antenna array.

1. 26. 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

3. 27. 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

4. 28. Detection principles for fast Rayleigh fading channels using an antenna array

   Författare :Anders Hansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; iterative decoding; serially concatenated coding; adaptive antenna arrays; multiple antennas; APP algorithm; diversity reception; Rayleigh channels; correlation; sequence detection; fading channels;

   Sammanfattning : .... LÄS MER

5. 29. Shape and material optimization for antenna applications

   Författare :Per Jacobsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; explicit-implicit time stepping; sensitivity analysis; Nitsche s method; total scattering cross section; shape and material optimization; array antennas; finite element method;

   Sammanfattning : In this thesis, a gradient-based method for shape and material optimization fortwo antenna applications is presented: minimization of the active reflectioncoefficient for conformal array antennas; and minimization of the totalscattering cross section for cylindrical scatterers. The sensitivity of theobjective function with respect to changes of the shape and material of the geometry isexpressed in terms of the original field problem and an adjoint field problem. LÄS MER

7. 30. Millimeter Wave Imaging and Phased Array Antennas for 5G and Aerospace Applications

   Författare :Jakob Helander; Teoretisk elektroteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; 5G; phased array; Millimeter wave antenna arrays; millimeter wave imaging; Computational Electromagnetics; Non-destructive testing NDT ; compressive sensing;

   Sammanfattning : Phased array antennas are cornerstones in many proposed antenna solutions concerning the next generation of both airborne radar systems and wireless communication systems (5G). Additionally, millimeter wave (mm-wave) frequencies are expected to play an integral role in 5G, and are deemed well-suited for inspecting structural components used in the aerospace industry. LÄS MER