Design and analysis of finite arrays of circumferentially oriented printed dipoles on electrically large coated cylinders

Abstract

Conformal antennas and arrays are used in a wide range of applications including mobile communication systems, missiles, aircrafts and spacecrafts. In these applications, the conformality is required for aesthetic and aerodynamic constraints and reducing the radar cross-section. Antennas and arrays conformal to the cylindrical host bodies are particularly important since cylindrical geometry can be used to approximate most of the practical problems and it is a canonical geometry. However, the available design and analysis tools for antennas/arrays conformal to cylindrical host bodies are either approximate methods or restricted to 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 aforementioned problem. In this work this method is used to analyze finite, phased arrays of circumferentially oriented printed dipoles conformal to the dielectric coated electrically large circular cylinders. The accuracy and efficiency of the method comes from the computation of the appropriate Green’s function which is the kernel of the electric field integral equation to be solved via MoM. There are three different high-frequency based representations for the Green’s function in the spatial domain which are valid in different but overlapping regions: Planar representation, steepest descent path (SDP) representation and the Fourier Series (FS) representation. These different representations are used interchangeably to obtain the most accurate solution that requires the least amount of computational time. Several modifications on the method are made in this work to increase the efficiency and accuracy of the solution. The effects of the array and host body parameters on the performance of the array are presented. The results are compared with a previously published spectral domain solution to show the accuracy of the method. Also, performance comparisons with those of the cylindrical arrays of axially oriented dipoles and planar arrays are made to observe the effects of curvature and the dipole orientation on the performance of the array.