Sökning: "Wideband Antennas"

Visar resultat 1 - 5 av 45 avhandlingar innehållade orden Wideband Antennas.

1. 1. 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

3. 2. Printable Green RFID Antennas for Embedded Sensors

   Författare :Yasar Amin; Hannu Tenhunen; Lirong Zheng; Qiang Chen; Leena Ukkonen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; RFID; Antennas; Inkjet printing; Wideband Antennas; Narrow-band Antennas;

   Sammanfattning : In the recent years, radio-frequency identification (RFID) technology has been widely integrated into modern society applications, ranging from barcode successor to retail supply chain, remote monitoring, detection and healthcare, for instance. In general, an RFID tag or transponder is composed of an antenna and an application-specific integrated circuit chip. LÄS MER

4. 3. Dielectrically Loaded Quad-ridge Flared Horns for Ultra Wideband Reflector Feed Applications in Radio Astronomy

   Författare :Jonas Flygare; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric loaded antennas; dielectric materials; reflector antenna feeds; radio astronomy; ultra wideband antennas; quad-ridge flared horn qrfh ; radio receivers; horn antennas; broadband antennas; aperture antennas.;

   Sammanfattning : Reflector-based radio telescopes are used as tools for observations in both radio astronomy and space geodesy. To observe the weak sources in space, highly sensitive receivers, fronted by optimized reflector feeds, are therefore needed. LÄS MER

5. 4. On signal processing and electromagnetic modelling : applications in antennas and transmission lines

   Författare :Jonas Lundbäck; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vector sensors; Statistical signal processing; Antennas; Directional Coupler; Tranmission lines; Partial discharge;

   Sammanfattning : This doctoral thesis is comprised of five parts. The first three parts concern signal processing and electromagnetic modelling of multiport antennas. The last two parts concern signal processing and transmission line theory applied to wave splitting on transmission lines. LÄS MER

7. 5. Topology optimization of antennas and waveguide transitions

   Författare :Emadeldeen Hassan; Martin Berggren; Daniel Noreland; Eddie Wadbro; Mats Gustafsson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Maxwell s equations; topology optimization; antennas; waveguide transition; finite-difference time-domain; gradient-based optimization; adjoint-field problem; microwave devices.; business data processing; administrativ databehandling;

   Sammanfattning : This thesis introduces a topology optimization approach to design, from scratch, efficient microwave devices, such as antennas and waveguide transitions. The design of these devices is formulated as a general optimization problem that aims to build the whole layout of the device in order to extremize a chosen objective function. LÄS MER