Microstrip patch antenna system having adjustable radiation pattern shapes and related method

An antenna device may include a ground plane, a first planar antenna element spaced above the ground plane and having an opening, and a second planar antenna element spaced above the first planar antenna element on a side of the first planar antenna element opposite the ground plane. The second planar antenna element may have a size smaller than the first planar antenna element. The antenna device may include a coaxial feed with an outer conductor, and an inner conductor surrounded by the outer conductor and extending outwardly from an end of the outer conductor. The outer conductor may be coupled to the ground plane and the first planar antenna element. The inner conductor may extend through the opening in the first planar antenna element and may be coupled to the second planar antenna element.