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dc.contributor.advisorErtürk, Vakur B.
dc.contributor.authorKaran, Şakir
dc.date.accessioned2016-01-08T18:19:43Z
dc.date.available2016-01-08T18:19:43Z
dc.date.issued2012
dc.identifier.urihttp://hdl.handle.net/11693/15515
dc.descriptionAnkara : The Department of Electrical and Electronics Engineering and the Graduate School of Engineering and Sciences of Bilkent University, 2012.en_US
dc.descriptionThesis (Ph. D.) -- Bilkent University, 2012.en_US
dc.descriptionIncludes bibliographical refences.en_US
dc.description.abstractNumerical methods based on Method of Moments (MoM) have been widely used for the design and analysis of planar microstrip antennas/arrays and printed circuits for various applications for many years. On the other hand, although the design and analysis of similar antennas/arrays and printed circuits on cylindrical structures are of great interest for many military, civil and commercial applications, their MoM-based analysis suffers from the efficiency and accuracy problems related with the evaluation of the Green’s function representations which constitute the kernel of the regarding integral equations. In this dissertation, novel closed-form Green’s function (CFGF) representations for cylindrically stratified media, which can be used as the kernel of an electric field integral equation (EFIE) are developed. The developed CFGF representations are used in a hybrid MoM/Green’s function solution procedure. In the course of obtaining the CFGF representations, first the conventional spectral domain Green’s function representations are modified so that all the Hankel (Bessel) functions are written in the form of ratio with another Hankel (Bessel) function. Furthermore, Debye representations for the ratio terms are used when necessary in order to avoid the possible overflow and underflow problems. Acceleration techniques that are present in the literature are implemented to further increase the efficiency and accuracy of the summation and integration. Once the acceleration techniques are performed, the resultant expressions are transformed to the space domain in the form of discrete complex images (DCIM) with the aid of the generalized pencil of function (GPOF) method and the fi- nal CFGF expressions are obtained by performing the resultant space domain integrals analytically. The novel CFGF expressions are used in conjunction with MoM for the investigation of microstrip antennas on cylindrically stratified media. The singular terms in mutual impedance calculations are treated analytically. The probe-fed excitation is modeled by implementing an attachment mode that is consistent with the current modes that are used to expand the induced current on the patches. In the course of modeling the probe-fed excitation, the probe-related components of CFGF representations are also derived for the first time in the literature and MoM formulation is given in the presence of an attachment mode. Consequently, several microstrip antennas and two antenna arrays are investigated using a hybrid MoM/Green’s function technique that use the CFGF representations developed in this dissertation. Numerical results in the form of input impedance of microstrip antennas in the presence of several layers as well as the mutual coupling between two microstrip antennas are presented and compared with the available results in the literature and the results obtained from the CST Microwave Studio.en_US
dc.description.statementofresponsibilityKaran, Şakiren_US
dc.format.extentxvii, 136 leaves, illustrationsen_US
dc.language.isoEnglishen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectCylindrically stratified mediaen_US
dc.subjectclosed-form Green’s function representationsen_US
dc.subjectdiscrete complex image methoden_US
dc.subjectgeneralized pencil of function methoden_US
dc.subjectMethod of Momentsen_US
dc.subjectinput impedanceen_US
dc.subjectmutual couplingen_US
dc.subject.lccQC174.17.G68 K381 2012en_US
dc.subject.lcshGreen functions.en_US
dc.subject.lcshMoment method.en_US
dc.subject.lcshAntennas ((Electronic)en_US
dc.subject.lcshMicrowave antennas.en_US
dc.titleMethod of moments analysis of microstrip antennas in cylindrically stratified media using closed-form Green's functionsen_US
dc.typeThesisen_US
dc.departmentDepartment of Electrical and Electronics Engineeringen_US
dc.publisherBilkent Universityen_US
dc.description.degreePh.D.en_US


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