Synthesis of pencil-beam antenna arrays with low dynamic range ratio of excitation coefficients

doctoral thesis

• Title (croatian): Sinteza antenskih nizova s uskom glavnom laticom i malim dinamičkim rasponom pobudnih koeficijenata
• Author: Katarina Vodvarka
• Mentor: Mladen Vučić (mentor)
• Committee member: Damir Seršić (predsjednik povjerenstva)
• Committee member: Zvonimir Šipuš (član povjerenstva)
• Committee member: Branimir Ivšić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; (Department of Electronic Systems and Information Processing); Zagreb
• Defense date and country: 2024-10-29, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

This dissertation considers the design of linear and planar pencil-beam antenna arrays with low dynamic range ratio (DRR) of excitation coefficients. Three new methods are proposed. The first method is based on convex optimization. It is suitable for the design of linear pencil beam arrays optimum in L1 sense. The obtained arrays exhibit maximum sidelobe level (SLL) of approximately -21 dB for all array sizes, with the lobes that monotonically decrease as the angle increases. The DRR of excitation coefficients of these arrays increases linearly with the number of elements and generally takes low values. The second method extends the design of L1 pencil beams. The original optimization problem is here equipped with the constraints set on maximum DRR and on maximum SLL. Unfortunately, the obtained problem is not convex. For its solving, a global optimization method is developed. It utilizes global search based on branch and bound algorithm that employs convex optimization and feasibility test for tree pruning. The method supports independent control of DRR and SLL. The third method is developed for the design of uniformly-excited unequally-spaced antenna arrays. The design of such arrays leads to nonlinear and nonconvex problems. For their solving, general-purpose methods for nonlinear optimization have been utilized. The application of these methods proved efficient in unconstrained and constrained design of linear and planar arrays with maximum beam efficiency and with maximum directivity.

Abstract (croatian)

U disertaciji je razmatran dizajn linearnih i planarnih antenskih nizova s uskom glavnom laticom i malim dinamičkim rasponom pobudnih koeficijenata (DRR). Predložene su tri nove metode za dizajn. Prva metoda temelji se na konveksnoj optimizaciji te je namijenjena za dizajn linearnih nizova s minimalnom L1-normom. Nizovi dobiveni predloženom optimizacijom imaju konstantnu razinu bočnih latica od otprilike -21 dB za sve veličine nizova te bočne latice koje padaju monotono s porastom kuta. DRR ovakvih nizova raste linearno s brojem elemenata te generalno poprima male vrijednosti. Druga metoda se temelji na globalnoj optimizaciji te predstavlja proširenje prve metode. Polazni optimizacijski problem ovdje je proširen dodavanjem ograničenja na maksimalan DRR i maksimalnu razinu bočnih latica. Nažalost, takav problem više nije konveksan pa je za njegovo rješavanje razvijena metoda grananja i ograničavanja koja za odsijecanje grana koristi konveksnu optimizaciju i test izvedivosti. Metoda podržava neovisnu kontrolu razine bočnih latica i DRR-a. Konačno, treći dizajn razmatra nizove s jednako pobuđenim nejednoliko razmaknutim elementima. Budući da su takvi problemi nekonveksni i nelinearni, za njihovo rješavanje predloženi su optimizacijski postupci opće namjene. Primjena ovih postupaka pokazala se učinkovitom u dizajniranju linearnih i planarnih nizova s maksimalnom učinkovitošću glavne latice i maksimalnom usmjerenošću.

• Keywords: antenna array; beam efficiency; branch and bound; convex optimization; directivity; dynamic range ratio; global optimization; L1-norm; nonlinear optimization; pencil beam; unequally spaced array; uniform excitation.
• Keywords (croatian): antenski niz; antenski niz s nejednoliko rasporedenim elementima; dinamički raspon pobudnih koeficijenata; globalna optimizacija; grananje i ograničavanje; jedinična pobuda; konveksna optimizacija; L1-norma; nelinearna optimizacija; ucinkovitost glavne latice; uska glavna latica; usmjerenost.
• Language: english
• URN:NBN: urn:nbn:hr:168:560269
• Promotion: 2024
• Project: Number: IP-2019-04-4189; Title: Učinkoviti sustavi za obradu signala namijenjeni programski definiranom radiju; Title: Efficient Signal Processing Systems for Software Defined Radio; Acronym: EfficientSDR; Leader: Mladen Vučić; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Research Projects
• Study programme: Title: 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)
• Type of resource: Text
• Extent: 106 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-11-28 12:47:24