Sökning: "antenna system"

Visar resultat 1 - 5 av 261 avhandlingar innehållade orden antenna system.

1. 1. Systematic Antenna Design Using the Theory of Characteristic Modes

   Författare :Zachary Miers; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Theory of Characteristic Modes; Antenna Design; Antenna; Characteristic Modes; Computational Electromagnetics; MIMO Systems; MIMO Antenna; MIMO; Mutual Coupling; Mobile Antenna;

   Sammanfattning : The day Faraday moved a magnet in and out of a wire loop and detected the time-varying magnetic field, the first wireless transmitter / receiver system was created and the world was changed forever. However, it took almost fifty years for Heinrich Hertz to use Maxwell's equations and Faraday's insights in his professorship at Karlsruhe to create the first electromagnetic wireless communication system using a spark gap dipole transmitter and a loop antenna-based receiver. LÄS MER

3. 2. 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. 3. 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

5. 4. Advanced Dual Circularly Polarized Antenna for Automotive Radar Systems

   Författare :Zhaorui Zang; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; radar; Antenna; polarimetric radar.; automotive; gap waveguide; dual circular polarization; low-profile;

   Sammanfattning : Advanced driver assistance systems (ADAS) promise reliable support for collision avoidance and cruise control. The demand for precise target classification and road surface sensing requires a sensor revolution. In this regard, the automotive radar system is highly expected to collect as much information as possible. LÄS MER

7. 5. Wideband Active and Passive Antenna Solutions for Handheld Terminals

   Författare :Peter Lindberg; Anders Rydberg; Anders Pers; Nicholas Buris; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering physics; active antennas; impedance matching; dipole antennas; baluns; slot antennas; microstrip antennas; mobile antennas; multifrequency antennas; antenna proximity factors; receiving antennas; ferrite devices; Teknisk fysik;

   Sammanfattning : This thesis presents solutions and studies related to the design of wideband antennas for wireless handheld terminal applications. A method of electrically shortening the terminal chassis length to obtain resonance at high frequencies has been proposed and evaluated, thereby increasing the antennas impedance bandwidth. LÄS MER