Elektriksel olarak büyük dielektrik kaplı silindirler üzerindeki çevresel doğrultuda faz dizimli baskı dipollerinin incelenmesi ve tasarımı

ABSTRACTDESIGN AND ANALYSIS OF FINITE ARRAYS OFCIRCUMFERENTIALLY ORIENTED PRINTEDDIPOLES ON ELECTRICALLY LARGE COATEDCYLINDERSBarış GünersuM.S. in Electrical and Electronics EngineeringSupervisor: Assist. Prof. Dr. Vakur B. ErtürkuAugust, 2004Conformal antennas and arrays are used in a wide range of applications includ-ing mobile communication systems, missiles, aircrafts and spacecrafts. In theseapplications, the conformality is required for aesthetic and aerodynamic con-straints and reducing the radar cross-section. Antennas and arrays conformal tothe cylindrical host bodies are particularly important since cylindrical geometrycan be used to approximate most of the practical problems and it is a canonicalgeometry. However, the available design and analysis tools for antennas/arraysconformal to cylindrical host bodies are either approximate methods or restrictedto small arrays. Recently, a hybrid method based on Method of Moments (MoM)combined with a Green?s function in space domain is proposed to solve the afore-mentioned problem. In this work this method is used to analyze finite, phasedarrays of circumferentially oriented printed dipoles conformal to the dielectriccoated electrically large circular cylinders. The accuracy and efficiency of themethod comes from the computation of the appropriate Green?s function whichis the kernel of the electric field integral equation to be solved via MoM. Thereare three different high-frequency based representations for the Green?s functionin the spatial domain which are valid in different but overlapping regions: Planarrepresentation, steepest descent path (SDP) representation and the Fourier Series(FS) representation. These different representations are used interchangeably toobtain the most accurate solution that requires the least amount of computationaltime. Several modifications on the method are made in this work to increase theefficiency and accuracy of the solution. The effects of the array and host bodyparameters on the performance of the array are presented. The results are com-pared with a previously published spectral domain solution to show the accuracyiiiivof the method. Also, performance comparisons with those of the cylindrical ar-rays of axially oriented dipoles and planar arrays are made to observe the effectsof curvature and the dipole orientation on the performance of the array.Keywords: Conformal phased arrays, Method of moments, Green?s function,Coated cylinders.