Numerical Modeling of Conformal Phased Arrays on Tactical Systems

Conformal phased arrays on missiles and other tactical military platforms are affected in their radiation behavior by the local surface geometry. This controls the array blind spot locations and are dominantly influenced by the creeping wave propagation between array elements. However, for an arbitrary location pair on the curved surface, the appropriate creeping wave formulation can be different and there exists no single formulation that is uniformly valid from the paraxial to the deep shadow region. In this paper, a criterion expressed in terms of the universal Fock parameter xi, for switching between two distinct creeping wave formulations is investigated empirically. This is accomplished by numerically comparing four different high-frequency formulations for source excited surface H_z and H_phi magnetic fields on conducting circular cylinders. Interestingly, the numerical results indicate that a single value for xi may not exist for both H_z and H_phi components, for a given axial separations and cylinder electrical radius ka. The results indicate need for development of advanced creeping wave formulations for improved modeling and performance analysis of flush-mounted conformal phased array systems