US Patent 7385555 System for co-planar dual-band micro-strip patch antenna

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.