Mutual coupling analysis of cylindrical waveguide arrays using hybrid SD-UTD method

The shape of a conformal antenna is mainly determined by radiation and scanning requirements, or by considerations, other than electromagnetic, such as aerodynamic/hydrodynamic shape demands. One way of analyzing conformal arrays is to use the separation of variables. This method can be generalized to include an arbitrary number of dielectric layers. The structures under consideration have one property in common: they are homogeneous in two dimensions and vary in the third. For each spectral component of the source, the excited electromagnetic field in the two directions for which the structure is homogeneous has the same harmonic variation as the source. Therefore, the original three-dimensional problem is transformed into a spectrum of simpler one-dimensional problems. Since each one-dimensional problem is solved in the spectral domain, this approach is called the spectral domain (SD) method. If the structure to be analyzed has a general, non-canonical shape (i.e. the structure is neither circular-cylindrical nor spherical), one can approximate the structure shape locally as cylindrical or spherical, or one can use some approximate method like the uniform theory of diffraction (UTD) (Pathak, P.H. et al., 1981). Although there are benefits in applying UTD, it is an approximate method and requires extra precautions before applying it. For example, it is very hard to analyze structures covered with a dielectric, especially if the dielectric is multilayered (Persson, P. and Rojas, R.G., 2003). The paper examines a hybrid SD-UTD analysis method.