NEW DESIGNS OF MICROWAVE FRACTAL RESONATORS FOR MODERN WIRELESS APPLICATIONS YAQEEN SABAH MEZAAL DAYYENI DECEMBER 2014 NEW DESIGNS OF MICROWAVE FRACTAL RESONATORS FOR MODERN WIRELESS APPLICATIONS A THESIS SUBMITTED TO THE GRADUATE SCHOOL OF NATURAL AND APPLIED SCIENCES OF ÇANKAYA UNIVERSITY BY YAQEEN SABAH MEZAAL DAYYENI IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN THE DEPARTMENT OF ELECTRONIC AND COMMUNICATION ENGINEERING DECEMBER 2014 STATEMENT OF NON-PLAGIARISM PAGE I hereby declare that all information in this document has been obtained and presented in accordance with academic rules and ethical conduct. I also declare that, as required by these rules and conduct, I have fully cited and referenced all material and results that are not original to this work. Name, Last Name: Yaqeen Sabah Mezzal, DAYYENI Signature : Date : 17.12.2014 iii ABSTRACT NEW DESIGNS OF MICROWAVE FRACTAL RESONATORS FOR MODERN WIRELESS APPLICATIONS DAYYENI, Yaqeen Sabah Mezaal Ph.D, Department of Electronic and Communication Engineering Supervisor: Prof. Dr. Halil T. EYYUBOĞLU Co-Supervisor: Prof. Jawad K. ALI December 2014, 132 pages In this dissertation, new microstrip bandpass and bandstop filters based on fractal resonators have been presented in an attempt to construct filter designs with smaller size for almost modern wireless applications. The proposed bandpass filter structures have been generated based on Moore, Hilbert, Hilbert-zz and Sierpinski fractal geometries while the proposed bandstop filter is based on Hilbert Fractal resonators. The space-filling property and the self-similarity of the configurations related to the consecutive iteration levels of these fractal geometries have been found to create compact filter structures with accepted performance results. Narrowband compact Moore fractal filters from 2nd and 3rd iteration levels have been designed for 2.4 GHz band application using a relative dielectric constant of 10.8 and dielectric thickness of 1.27 mm with good performance results in their quasi elliptic responses. For 3rd iteration Moore bandpass filter, size reduction percentage iv as compared with 2nd iteration one resonating at the same frequency and using the same substrate material for 3rd iteration structure is 43% .The simulated and measured results are well-matched to each other . Stepped impedance Hilbert microstrip bandpass filters have designed with characteristics of compacted sizes and narrow band responses which are the requisites of recent wireless communication systems. These filters are built from two edge coupled resonators, each resonator has been achieved by applying step impedance resonator generator on 1st and 2nd iterations of Hilbert fractal resonators on each segment for each fractal iteration . They have been proposed for the ISM band applications at center frequency of 2.4 GHz using a substrate with a dielectric coefficient of 9.6 and thickness of 0.508 mm. Results show that these filters own satisfactory output frequency responses. Size reduction percentage as compared with 1st iteration stepped impedance Hilbert bandpass filter operating at similar frequency and using similar substrate material for 2nd iteration structure is 63.34% . New fractal design scheme based on Hilbert-zz curve has been used to produce compact microstrip bandpass filter .This fractal filter has been realized using two coupled resonators using additional coupling stubs .The material substrate has relative dielectric constant of 9 and thickness of 1.27 mm. Simulation graphs demonstrate that these filters possess good transmission and return loss features for the resultant frequency responses. It should be mentioned that Moore, stepped impedance Hilbert resonator and Hilbert- zz bandpass filters exhibit higher harmonics eliminations in out of passband regions of their frequency responses which are much desired properties in modern wireless communications. Miniaturized microstrip bandpass filters have been designed using Sierpinski fractal curves from 0th to 3rd iteration levels. The intended filter designs have been performed using dual-mode square slotted microstrip resonator in accordance with adopted fractal iterations. These microstrip bandpass filters have less bandwidth and sharper transmission responses than those of the single mode resonator and traditional square patch filter. Filter structures generating from the successive v iterations of the applied fractal geometries exhibit a noticeably low insertion loss, and sharper response of about 1% fractional bandwidth as compared with the conventional microstrip square patch filter of 3% fractional bandwidth constructed at the same resonant frequency of 5.33 GHz and using substrate material of dielectric coefficient of 10.8 and thickness of 1.27 mm. A new dual-band microstrip bandpass filter has been designed using Peano fractal geometry at resonant frequencies of 2.25 GHz and 4.825 GHz using a substrate of a relative dielectric constant of 10.8 and thickness of 1.27 mm. The topology of this filter consists of dual edge coupled resonators constructed from 1st iteration of Peano fractal geometry. Simulated responses show that this filter has well frequency responses as well as dual bands gained which are highly requested in current communication systems. On the other hand, new designs of Wide Bandpass Filter (WBPF) and Narrow Bandstop Filter (NBSF) based on Hilbert fractal resonators have been investigated using Sonnet simulator. The frequency responses properties of the proposed filters have been studied to observe the corresponding broad bandpass and narrow bandstop behaviours at the frequency around 2GHz.Moreover, the phase dispersion and surface current density details about proposed filters have been presented and analyzed. The proposed fractal filters have been found to possess compact sizes with flexible designs in addition to good frequency responses. The modeling, simulation and performance evaluation have been performed using the method of moment (MoM) package Microwave Office 2009 from Advanced Wave Research (AWR) and a full-wave based electromagnetic simulator Sonnet software package which are very commonly used in electronics industry and research institutions. Keywords: Microstrip Fractal Resonators, Compact Bandpass and Bandstop Filters, Narrow Bandpass Filters, Wide Bandpass Filter, Narrow Bandstop Filter, Frequency Harmonic Suppressions. vi ÖZ MODERN KABLOSUZ UYGULAMALAR İÇİN MİKRODALGA FRAKTAL REZONATÖRLERİNİN YENİ TASARIMlLARI DAYYENI, Yaqeen Sabah Mezaal Doktora, Elektronik ve Haberleşme Mühendisliği Anabilim Dalı Tez Yöneticisi: Prof. Dr. Halil T. EYYUBOĞLU Eş Tez Yôneticisi: Jawad K. ALI Aralık 2014, 132 sayfa Bu tezde, yeni fraktal mikroşerit bant geçiren ve bant durduran filtre tasarımları modern kablosuz uygulamalar için daha küçük boyutu ile filtre tasarımlar üretmek amacıyla geliştirmiştir. Önerilen Bant-geçiren filtre yapıları Moore, Hilbert, Hilbert-zz ve Sierpinski fraktal geometrilerine dayanarak oluşturulurken. Önerilen bant durduran filtresi Hilbert Fraktal rezonatörlere dayanmaktadır. Bu dallanmış geometrilerin ardışık yineleme seviyelerine karşılık gelen yapıların boşluk doldurucu özelliği ve kendi kendine benzerliğı kabul edimiş performanslı indirgenmiş boyutlu filtre yapılarnın üretilmesi için tespit bulunmuştur. İkinciden Üçüncü yinelemeye dar bant kompakt Moore fraktal filtreleri, nispi dielektrik sabiti 10.8 ve dielektrik kalınliğı 1.27 mm olan ve yarı eliptik sonuç vii performansları iyi olan durumlerı kullanılarak 2.4 GHz bant uygulaması için tasarlanmıştır. Üçüncü yinelemeli Moore bant-geçiren filtre için, ikinci yinelemeye göre aynı frekansta boyut küçültme yüzdesi için % 43 tur , üçüncü yineleme için aynı substrate materyalini kullanarak. Simülasyon ve ölçülen sonuçlar birbirine uyumludur. Kademeli empedans Hilbert mikroşerit bant-geçişli filtreler Modern telsiz iletişim devrelerinin gereksinimleri kompakt büyüklükte ve dar bantlı tepkilerinin özellikleri ile tasarladık.Bu filtreler çift kenar kuplajlı rezonatörden inşa edilmiştir, her rezonatör her fraktal yineleme için her segmentinde Hilbert fraktal rezonatörlerin birinci ve ikinci yineleme adım empedans rezonatör jeneratör uygulanmasına dayanmaktadır.Bu filtereler 9.6 nispi dielektrik sabiti ve 0.508 mm kalınlık ile 2.4 GHz merkez frekansında ISM bant uygulamaları için tasarlanmıştır.Sonuçlar bu filtrelerin iyi iletime sahip ve geri dönuş kaybı özellikleri olduğunu göstermektedir. İkinci yinelemeli Kademeli empedans Hilbert mikro bant-geçişli filtre için,ilk yinelemeye göre aynı frekansta boyut küçültme yüzdesi için % 63,34 'tür, İkinci yineleme filtere için aynı substrate materyalini kullanarak. Hilbert-zz eğrisine dayalı yeni fraktal tasarım 9 nispi dielektrik sabiti ve 1.27 mm kalınlığında bir substrat kullanılarak ek bağlantı taslakları ile iki kutup kapasitif birleştiğinde mikro bant-geçiren filtre kompakt oluşturmak için getirilmiştir. Sonuçlar bu filtrelerin iyi iletime ve çıkış frekans tepkisinin ve geri dönuş kaybı özellikleri sahip olduğunu göstermektedir. Moore , kademeli empedans Hilbert rezonatör ve Hilbert-zz bant geçiren filtreleri kendi freakrans tepkilerinin bant geçiren bölgelerin dışında yüksek harmonik bastırma özelliği sergiler , ki bunlar modern telsiz iletişimi için çok istenen ve şaşırtıcı özellikerdir. Minyatür mikroşerit bant geçiren filtreler, üçüncü yineleme seviyelere sıfırıncı gelen Sierpinski fraktal eğrileri kullanılarak dizayn edilmiştir.Önerilen filtre tasarımı, viii terçih edilen fraktal yinelemeye