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doctoral thesis
Nizovi kružnih valovodnih antena na sfernim strukturama
Zagreb, Osijek: University of Zagreb, Faculty of Electrical Engineering and Computing, 2009. urn:nbn:hr:168:004328
Rupčić, Slavko
University of Zagreb
Faculty of Electrical Engineering and Computing
Department of Communication and Space Technologies
Josip Juraj Strossmayer University of Osijek
Faculty of Electrical Engineering, Computer Science and Information Technology Osijek

Institutional repository: FER Repository

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Rupčić, S. (2009). Nizovi kružnih valovodnih antena na sfernim strukturama (Doctoral thesis). Zagreb: University of Zagreb, Faculty of Electrical Engineering and Computing; Osijek: Josip Juraj Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek. Retrieved from https://urn.nsk.hr/urn:nbn:hr:168:004328

Rupčić, Slavko. "Nizovi kružnih valovodnih antena na sfernim strukturama." Doctoral thesis, University of Zagreb, Faculty of Electrical Engineering and Computing; Josip Juraj Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek, 2009. https://urn.nsk.hr/urn:nbn:hr:168:004328

Rupčić, Slavko. "Nizovi kružnih valovodnih antena na sfernim strukturama." Doctoral thesis, University of Zagreb, Faculty of Electrical Engineering and Computing; Josip Juraj Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek, 2009. https://urn.nsk.hr/urn:nbn:hr:168:004328

Rupčić, S. (2009). 'Nizovi kružnih valovodnih antena na sfernim strukturama', Doctoral thesis, University of Zagreb, Faculty of Electrical Engineering and Computing; Josip Juraj Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek, accessed 18 February 2025, https://urn.nsk.hr/urn:nbn:hr:168:004328

Rupčić S. Nizovi kružnih valovodnih antena na sfernim strukturama [Doctoral thesis]. Zagreb: University of Zagreb, Faculty of Electrical Engineering and Computing; Osijek: Josip Juraj Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek; 2009 [cited 2025 February 18] Available at: https://urn.nsk.hr/urn:nbn:hr:168:004328

S. Rupčić, "Nizovi kružnih valovodnih antena na sfernim strukturama", Doctoral thesis, University of Zagreb, Faculty of Electrical Engineering and Computing, Zagreb; Josip Juraj Strossmayer University of Osijek, Faculty of Electrical Engineering, Computer Science and Information Technology Osijek, Osijek, 2009. Available at: https://urn.nsk.hr/urn:nbn:hr:168:004328

Metadata
TitleNizovi kružnih valovodnih antena na sfernim strukturama
Title (english)Circular waveguide antenna arrays on spherical structures
AuthorSlavko Rupčić
MentorZvonimir Šipuš (mentor)
Committee memberJuraj Bartolić (predsjednik povjerenstva)
Committee memberZvonimir Šipuš (član povjerenstva)
Committee memberNikša Burum (član povjerenstva)
Committee memberRudolf Scitovski (član povjerenstva)
Committee memberRadovan Zentner (član povjerenstva)
GranterUniversity of Zagreb
Faculty of Electrical Engineering and Computing
(Department of Communication and Space Technologies)
Zagreb
GranterJosip Juraj Strossmayer University of Osijek
Faculty of Electrical Engineering, Computer Science and Information Technology Osijek
Osijek
Defense date and country2009-01-30, Croatia
Scientific / art field,
discipline and subdiscipline		TECHNICAL SCIENCES
Electrical Engineering
Universal decimal classification
(UDC)		621.3 - Electrical engineering
Abstract
Konformni antenski nizovi, odnosno konformne antene su nizovi koji se prilagođavaju podlozi na koju su postavljene. Kao antenski elementi konformnih nizova u mikrovalnom frekvencijskom području često se koriste otvori na konformnoj strukturi. Valovodom pobuđeni otvori su poznati po velikoj širini glavne latice, simetričnom polju kod antenskog skeniranja, dobrom prilagođenju impedancije (admitancije) te karakteristici ponašanja visokopropusnog filtra (zbog granične frekvencije valovodnih modova). Veliki kut skeniranja uz dovoljno male dimenzije jedna su od važnijih karakteristika konformnih nizova s otvor antenama. U radu su teoretski analizirani i eksperimentalno izmjereni su bitni parametri antenskih nizova na sfernoj podlozi pri čemu su kao elementarne antene korišteni valovodi kružnog poprečnog presjeka. U svrhu analize razvijen je teorijski model, odnosno numerička metoda zasnovana na numeričkom rješavanju integralne jednadžbe za magnetsko (električno) polje primjenom metode momenata. Spektralnom metodom je trodimenzionalni problem transformiran u spektar jednodimenzionalnih problema, što je znatno pojednostavilo i ubrzalo rješavanje analiziranih problema. Pri izračunu parametara niza korištene su Greenove funkcije za sferne strukture u spektralnoj domeni. Na temelju razvijene metode analize izrađen je računalni program za izračun ulazne admitancije, sprege između valovoda na sferi te dijagrama zračenja (i polarizacije) valovodnih antenskih nizova na sfernoj podlozi. Da bi se pri izračunu sprege izbjegli numerički problemi, uvedene su modificirane vektor- Legendreove transformacije i normalizirani Legendreovi polinomi. Osim toga, pri izračunima su korišteni asimptotski izrazi za Besselove i Hankelove funkcije. Pri izračunu sprege uvedena je nova metoda kod koje su, korištenjem analogije sa metodom potencijala te adicionog teorema za sferne harmonike, određeni izrazi za ekvivalentne struje u spektralnoj domeni na otvoru valovoda. Ovom metodom je značajno smanjeno vrijeme za izračun koeficijenata sprege. Utjecaj zakrivljenosti podloge na parametre antene razmatran je izračunom svih bitnih parametara valovodnog antenskog niza na sferi (ulazna admitancija, koeficijenti sprege, međuadmitancija i dijagramim zračenja) i usporedbom istih za različite radijuse sferne podloge. Teorijski model je verificiran izveden korištenjem mjerenih rezultata iz dostupne literature te mjerenjem na izvedenim laboratorijskim modelima (dva planarna i dva sferoidalna modela). Na oba laboratorijska modela načinjena su mjerenja sprege i dijagrama zračenja. Ova mjerenja nisu izvedena u bezječnoj komori, što je rezultiralo na pojavom neželjenih reflektiranih valova, a time i odstupanjima i valovitosti u izmjerenim karakteristikama antene. U svim izmjerenim slučajevima postignuto je dobro poklapanje izračunatih i izmjerenih rezultata, čime je potvrđena ispravnost teorijskog modela i prema njemu izvedenog računalnog programa.
Abstract (english)
considerations other than electromagnetics. Usually, a conformal antenna is cylindrical, spherical or some other shape, with radiating elements mounted on or integrated into the smoothly curved surface. Radiation elements – elementary antennas of these arrays are usually used aperture antennas. Apertures are microwave antennas that are usually loaded with rectangular or cylindrical waveguides. The radiation pattern of a single waveguide opening is very broad. In the thesis we studied a spherical array of circular waveguides antennas with the apertures placed on the spherical surface. The analysis is based on solving the integral equation for a magnetic field by using the moment method (MoM). The solution procedure takes advantage of the spectral domain approach where a three-dimension problem is transformed into spectral of much simpler onedimension problem. The antenna structure is rigorously taken into account by using proper Green’s functions, and the array is fully analyzed by using the element-by-element approach. A theoretical model to determine solutions for a radiation pattern, mutual coupling and input admittance was developed. We have also made the program for calculating radiation pattern, mutual coupling and input admittance of spherical waveguide arrays based on the developed MoM and spectral-domain approach. In order to avoid numerical problems, when we calculate mutual coupling, a modified vector- Legendre transformation and normalized Legendre polynomials are defined and applied to the solution procedure. We have also used asymptotic equations for Bessel and Hankel functions. This thesis demonstrates a novel approach to mutual coupling within the MoM analysis of spherical arrays by expressing the equivalent current on the waveguide aperture in terms of two suitable potential-like auxiliary functions. The new approach results in significant acceleration of the analysis of spherical antenna arrays. The influence of structure radius on input impedance, mutual coupling and radiation pattern was also investigated. In the proces of verifying theoretical results we had to built two planar and two spherical experimental models. On the spherical surface, antenna elements are placed at equidistant positions on the surface of the icosahedron. The developed theoretical model and program have been verified against measurements and results from the literature. Measurement was not performed in a well-defined anechoic chamber. The results show a very good agreement between the measured and the calculated results.
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:168:004328
ProjectNumber: 036-0361566-1570
Title: Elektromagnetski učinci i strukture u komunikacijskim sustavima
Leader: Zvonimir Šipuš
Jurisdiction: Croatia
Funder: MZOS
Funding stream: ZP
ProjectNumber: 165-0361630-1636
Title: Adaptivni prijenos videosignala radijskim mrežama u heterogenom okruženju
Leader: Snježana Rimac-Drlje
Jurisdiction: Croatia
Funder: MZOS
Funding stream: Nema
ProjectNumber: 165-0362027-1479
Title: Širokopojasni pristup i internetske usluge u ruralnim područjima
Leader: Drago Žagar
Jurisdiction: Croatia
Funder: MZOS
Funding stream: Nema
Study programmeTitle: Doctoral study programme "Electrical Engineering and Computing"
Study programme type: university
Study level: postgraduate
Academic / professional title: doktor/doktorica znanosti, po-dručje tehničkih znanosti (doktor/doktorica znanosti, po-dručje tehničkih znanosti)
Catalog URLhttp://lib.fer.hr/cgi-bin/koha/opac-detail.pl?biblionumber=33283
Type of resourceText
Extent184 str.
File originBorn digital
Access conditionsClosed access
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Created on2020-03-20 11:36:59