Characterizing helical microstrip antenna mounted on a dielectric-coated circular cylinder using MoM and closed-form Green´s function

A method of moments (MoM) and closed-form Green´s function approach are employed to characterize the radiation pattern of a center-fed helical microstrip antenna mounted on a superstrate of a circular conducting cylinder. An analytic expression for the current on the helical microstrip antenna is rigorously obtained by solving a mixed potential integral equation (MPIE) in the spatial domain. With the analytic expression for the current, radiation patterns of the helical antenna can be calculated analytically using the far-field Hankel transform. The proposed method can be easily applied to analyze the effects of substrate and superstrate on the radiation pattern of the helical antenna. A good agreement between the results of the presented Green´s function and MoM approach and those of the reciprocity approach provides validation for the presented method.