A multilayer antenna structure configured to receive Global Navigation
Satellite System (GNSS) and augmentation signals. The antenna includes a
microstrip patch radiation element disposed at a top layer and a ground
plane forming a first interior layer, the ground plane including at least
two coupling apertures, and the ground plane isolated from said radiation
element by a low loss dielectric. The antenna structure also includes a
bottom layer, the bottom layer is isolated from the ground plane by
another dielectric; at least two feed lines operably connected to a
hybrid coupler disposed on the bottom layer; and an active circuit on the
bottom layer, a first port of said active circuit operably connected to
the hybrid coupler.