Microstrip phased-array antennas : a finite-array approach Citation for published version (APA): Smolders, A. B. (1994). Microstrip phased-array antennas : a finite-array approach. [Phd Thesis 1 (Research TU/e / Graduation TU/e), Electrical Engineering]. Technische Universiteit Eindhoven. https://doi.org/10.6100/IR423038 DOI: 10.6100/IR423038 Document status and date: Published: 01/01/1994 Document Version: Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. 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If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim. Download date: 10. Feb. 2023 Microstrip Phased-Array Antennas: A Finite-Array Approach PROEFSCHRIFT ter verknjgmg van de graad van doctor aan de Techmsche Universitelt Eindhoven. op gezag van de Rector MagTIlficu~" prot.dr. lH" ~an Lint. voo!" een commlssle aange'Wczen door hct College van Dekanen in het openbaar tc vcrdedlgen op woensdag 5 oktober 1994 te 16..00 uur door Adrianus Bernardus Smolders geboren te l-lJlvarenbeek Dit procf<;chnft l~ goedgekeurd doof de promotoren prof.dr. A.G. Tijhui.. . en prof.dr.ir. G. llrussaard copromolOr dr. M.E.". Jeuken. CIP-DATA KONINKLIJKE BlBLiOTlIEbK, DEN HAAG Smolder~, Adrianul, Bernardu~ Mlcrmtnp phascd-arm} antcnna~ 11 hnite-ana)' apPI'OJ.ch ! Adl'lanu~ Rernardul, Smolder,~ - Emdho~en Uni~elslty of lechnology.. - TIL, fig .. , photos, lab .. The'l,~ Eindhoven - With ref - With Sllmm,uy 111 Dutch, TSBN 90-3R6-0010"O NUGI ::132 Subject he<ldIng~:: nlIcro~tl'lP antennas / mlCl'o~trlp aria} ~ j pha~eJ arr,l),,' @ 1994 hy A .. B Smolder" ElI1dhoven All right~ re~en,ed No pan 01 lhl~ publIcatIOn may be leproduccd or lramrIlltted In any form or b~ dn~ Illedn.~. dectronlC, mechanical, Illdudmg photo(;opy. re.cofding, or any mIOrnH\!IOrl qor,lge and rctnc,"al 'J,(elll. v.ithollt the prror v"ntten perml,~,ion 01 the COpy light Ov.l1cr, To ~tudy to finish, to publish Benjamin Franklin (1706.1790) At!/! Annet en I11ljn. OLl.der.~ Thl~ ~tudy wa~ performed ,(.~ part of the rc~carch program of the Electr0magllctlC~ Dlvi~inl1, Department of Electncal Engmeering, Eindhoven University of Technulug~. PO Bo)\. 51 J, 5600 MI3 Emdhoven, The Ncthcrlal1d~ Thrs v,ork v.<l$ ~upportd by the Technology Poundallon (STW) vii Abstract In thIs thesi~, the results are presented of a theoretical and experimental investigation of isolated microstrip antenna~ and of finite mIcros trip phased-array antcnna~.. Microstnp antennas have several features, including lIght weight, conformabiHty and low production costs, ",hieh make them interestIng candidates for several applIcations where a phased-array antenna i~ required The theoretical analYSI~ of finite arrays of microstrip antennas is based on a rigorous spcetral domaIn method-of-moments procedure The electromagneUc field is expressed in terms of the cxact spectral-domain dyadic Green's function Mutual coupling and surface wave effects are automatically included in the analysis. Small arrays and array element~ ncar the edge of an arra) can also be analysed with this fimte-array approach.. In addition, a sophisticated model for the feedIng coaxlal cables is developed In thIs wa)', electrically thIck and thus broadhand mierostnp configurations can be analysed An analytical extraction technIque IS proposed to reduce the required CPU time .. The theoretical model is validated hy comparing the calculated resuUs with measured data from several experiments.. Generally, a good agreement between theory and experiment IS obtained Some teehmques to improve the available bandwidth of mlcrostrip antennas are discussed Band",idths ranging from 20% to 50% have been obtaIned for isolated mlerostrip antennas When such broadband elements arc used in an array of microstrip antenoas, the handwidth IS reduced sIgnificantly due to mutual coupling Contents 1 Introduction 1 I 1 General introduction 1 2 Modelling approach 8 I 3 Orgamsation of the thesIs 9 2 Green's functions of a grounded two-layer dielectric structure 11 2..1 IntroductIOn II 2 2 Boundary-value problem 14 2 3 Spectral-domain solution 19 24 Electric and magnetIc fields in the spatial domain 28 3 Isolated microstrip antennas 33 3 I IntroductlOn 33 3 2 Model description 33 3 2 .. 1 Two-layer stacked microstrlp antenna 33 3.22 ThIn-substrate model 34 3 .. 2 .. 3 ThIck-substrate model 35 :1:1 Method-of-moments formulation 37 3 4 Basis functions 44 34 1 BasIs functions on the patches 45 3 4 2 Basis functions on the coaxIal probe 50 3 4 3 Attachment mode 51 ::'I 5 Calculation of the method-ol~moment matnx IZ] and IV""] 53 3 6 Input Impedance 54 3.7 Radiation pattern 57 3 .. 8 ComputatIOnal and numerical details 63 381 Introduction 63 3 .. 8..2 Surface waves and other singulanties 64 3fU Asymptotic-form extraction technique 68 IX x 3 9 Re~ults 94 3 .. 9 I Vahdation of the model 94 392 Single-layer mlcrostrip antennas 98 3 9 3 Stacked micrmtrJp antcnna~ 99 3 94 Broadband multilayer structurc); 104 3 .. 9 .. 5 Dlial-lrequency/du(ll-polarl~ation mlcro~tnp Hntennas 106 .1 9 .. 6 Broadband EMC mlcrostrip ant.ennas 107 111 4 Finite arrays of microstrip antennas 4 .. 1 Introduction III 4 .. 2 ConfiguratIon 114 4..3 Method-of-moments formulation 115 4..4 Port admittance matrix and scatlering matrix 120 4 5 Radiation characten~ties 121 4 6 CirculaJ po1arl~atl0n 12.1 4 7 ComputatIOnal and numerIcal details 124 48 Results IJ 1 4.81 Introduction 131 4 .. fl 2 Single-layer mICroS trip arrays 132 4 .. 8 J Stacked micrmtnp array ~ 140 4.K4 MultIlayer microstrip array~ 143 4 fl.':; Array of broadband CMC microstrip antenna~ 146 486 Far-field pattern of a finite mierostfip array 149 4 .. R 7 Circular polari~at1Un 151 4 .. R S Dual-frequency circularly polansed mlcro~tnp suharray 154 4() finite array of monopoles embedded In 11 grounded dielectnc ~Iab 15K 5 Summary and conclusions 163 A Expressions for the elements of IX.I 167 B Expressions [or the elements of IV'"I 177 Bibliography 1R1 Samcnvatting 191 Curriculum Vitae 193 Dank\\oord 195 List of abbreviations AR Axial Ratio, BW Bandwidth, CPU Central Processing Unit, EMC ElectroMagnetically Coupled, EUT Emdhoven UniversIty of Technology, G,\A~ Gallium ArsenIde, INMARSAT INternatIOnal MARItime SATellite organisation, MMIC Monolythie Microwave Integrated Circuit, SAR Synthetic Aperture Radar, n. Transverse Electric, TEM Transverse ElectroMagnetIc, TM Tran~ver~e Magnetic, T/R module Transmitter/ReceiH:r module, VSWR Voltage Standing Wave Ratio XI Chapter 1 Introduction 1.1 General introduction Hi~wry One of the prinCIpal characteristics of human bemgs I, that they almost continually !-.end and receive ~ignals to and from one another.. The exchange of meamngful signals is the heart of what i~ called communication .. In Its sunplest form, communication mvolves two people, namely the ~Ignal transmitter and the signal recetver.. These signals can take many forms.. Words are the mmt common form They can he either written or spoken .. Before the invention of technical resources such as radio communicatlon Or telephone, long-di,tance communication wa, very difficult and usually took a lot of time Proper long-distance commufilcation was at that tune only possible b) exchange of wntten words" CourIers were u,~ed to transport the mes~age from the .~endcr to the rccener Sl1lee the ImentlOn of radIO and telephone, far-distance commumcation or telecommUnICatIOn i~ possible, not only of written words" but also of spoken word~ and almost without any time delay between the transmISSIon and the receptIOn of the signal Antennas have played an important part In the development of our present telecommunicatIOn services Antennas have madc It posMble to commUnicate at far distances, without the need 01 a physIcal connecllon between the ,>ender and receiver,. Apart from the t.ender and receiver, there IS a third unpOltant element in a communicatlon ~)t.tem, namely the propagatton channeL The trammitled signals mOlY detenorate "" hen they propagate through tillS channel In this thesis only the antenna part of a communicatIOn ~y,tem WIl! be inve~tigated .. In 1g 86 Heinrich Hertz, who wa~ a professor of physics at the Technical Institute lTI Karlsruhe, \'iU:' the first person who made a complete radio system [33} When he produced spark'> at a gap of the transmitting antenna" sparking al~o occurred at the gap of the receiving antenna,. Hertz lTI fact v I~Llaliscd the theoretical po~tulatlOns of Jame~ Clerk Maxwell Hertz's first expenments u<;;ed