Hybrid numerical-asymptotic method for the calculation of the coupling between elements of a conformal microstrip patch array

Efficient asymptotic solutions have been developed for the calculation of the self and mutual coupling between patches on a curved 2D surface with variable curvature. For the calculation of the mutual coupling the approach is based on a local circular cylindrical approximation of the surface and on an asymptotic evaluation of the exact dyadic Green´s function for a substrate on a circular cylinder. For the calculation of the self-coupling of a patch the curvature of the substrate is neglected and the corresponding Green´s function is replaced by the Green´s function of a planar layer. The Sommerfeld integrals are calculated by using the Discrete Complex Image Method after having extracted the surface wave contributions. The dyadic Green´s function based on the two approaches is introduced in the mixed potentials electric field integral equation which is solved by using the RWG (Rao, Wilton, Glisson) triangular basis functions.