Abstract: A multioctave microstrip antenna for mounting to one side of a ground plane and including a metal foil spiral-mode antenna element and a dielectric substrate positioned between the antenna element and the ground plane. The spiral-mode antenna element has a frequency-independent pattern formed therein, such as a sinuous, log-periodic, tooth, or spiral pattern. The antenna can be mounted substantially flushly to the surface of a structure without perforating the surface of the structure and can be conformed thereto. The antenna exhibits a broad bandwidth, typically on the order of 600%.

Abstract: A magnetic corrugated horn antenna system is disclosed. This system includes a magnetic hybrid-mode horn antenna composed of a circular waveguide and a corrugated horn antenna which has a thin magnetic coating on its inner wall. The corrugation of the conical horn helps it to produce equal E-plane and H-plane patterns with low sidelobes. The magnetic coating can enhance or duplicate the beneficial effects of the corrugation, while avoiding the high gain loss and poor patterns reported in prior art systems that relay only on corrugated horns.