Abstract: An array antenna is arranged in an innovative sparse trifilar configuration. The antenna elements forming the array antenna are arranged to form three non-linear arrays. The antenna elements are approximately aligned to a triangular lattice structure with the antenna elements of each non-linear array occupying adjacent lattice positions. The three non-linear arrays are separated from each other by vacant lattice positions, thereby making the configuration a sparse array.

Abstract: An antenna assembly includes a conducting ground plane, a single dielectric substrate layer or a plurality of dielectric substrate layers each with different dielectric constants mounted to the conducting ground plane. A central patch element is mounted to the dielectric substrate layer or layers and configured to radiate within a first frequency band. A plurality of probes (i) extend through the conducting ground plane and the dielectric substrate and (ii) are physically connected to the central patch element. A parasitic ring is disposed around the central patch element and reactively coupled thereto. The parasitic ring is configured to radiate within a second frequency band.