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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

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Showing 21 to 24 of 24 (0.061 seconds)

Spelling suggestions: "subject:"electromagnetic band gap"" "subject:"clectromagnetic band gap""

21

Low-Profile Wideband Antennas Based on Tightly Coupled Dipole and Patch Elements

Irci, Erdinc 21 October 2011 (has links)
No description available.
Electrical Engineering
Electromagnetics
ultrawideband antenna
phased array
current sheet array
tightly coupled array
frequency selective surface
electromagnetic band gap
microstrip patch antenna
microstrip patch array
antenna miniaturization
bandwidth enhancement
small antennas
22

Syntéza struktur s elektromagnetickým zádržným pásmem / Synthesis of electromagnetic bandgap structures

Šedý, Michal January 2009 (has links)
In microwave frequency band, the planar technology is mainly used to fabricate electronic circuits. Propagation of surface waves belongs to the significant problem of this technology. Surface waves can cause unwanted coupling among particular parts of the structure and can degrade its parameters. The problem can be solved using an electromagnetic band gap structure (EBG). These periodic structures are able to suppress surface waves in different frequency bands. This thesis is focused on the modeling of these structures in the program COMSOL Multiphysics.
23

Planární antény na substrátech s elektromagnetickými zádržnými pásmy / Planar Antennas on Electromagnetic Bandgap Substrates

Horák, Jiří January 2009 (has links)
Planar antennas are used in several technical applications. The family of planar antennas contains microstrip antennas, which are very popular due to the low weight, low profile, simple manufacturing and easy mass production. Lower gain and excitation of surface waves are disadvantages of microstrip antennas. The propagation of surface waves can be efficiently suppressed if the conventional substrate is replaced by an electromagnetic bandgap (EBG) substrate. Microstrip antennas on EBG substrates have been presented in an open literature for several years. Nevertheless, no published work is devoted to the design of EBG substrates, which can suppress surface waves at several frequencies those cannot be covered by a single bandgap. In order to reach optimum parameters of designed antennas, selected global optimization methods are applied (genetic algorithms, particle swarm optimization, ant colony optimization).
24

Antény pro oblasti (sub)milimetrových vln / (Sub)millimeter-Wave Antennas

Pítra, Kamil January 2014 (has links)
Disertační práce se zabývá návrhem a optimalizací kruhově polarizované anténa pro oblast terahertzových kmitočtů. V práci se věnuji zjednodušené teorii terahertzového zdroje a návrhu vhodné antény pro tento zdroj. Návrh je zaměřen na dosažení kruhové polarizace z lineárně polarizovaných antén. Abych potlačil šíření povrchové vlny na elektricky tlustém dielektrickém substrátu, věnuji se návrhu a optimalizaci specifických periodických struktur. Návrh těchto struktur je poměrně komplikovaný, protože neexistuje přímočarý vztah mezi vlastnostmi struktur s elektromagnetickým zádržným pásmem (EBG) a geometrií buňky. Abych vhodně koncentroval vyzařovanou energii do úzkého svazku, věnuji se návrhu a optimalizaci částečně odrazného plochy (PRS), které působí jako planární čočka pro terahertzovou anténu.

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