Abstract: A wideband antenna element includes a conductive plate parallel to, and spaced from a ground plane. A tapered dielectric material is positioned between the plate and ground plane. A pair of driving points to the plate are positioned fixed distances on either side of a center interconnect point between the plate and ground plane, to effect staggered tuning of the antenna element.

Abstract: A frequency selective surface (FSS) for incorporation into the outer skin of an aircraft, for transmitting electromagnetic energy in a predetermined frequency band. The FSS includes three layers sandwiched together with a dielectric material. Arrays of apertures are formed in the two outer layers, which are conductive. The inner layer consists of patches of conductive material. The apertures and patches are in substantial alignment with one another. The apertures and patches can have the shapes of crossed-dipoles, circles, squares, tripoles and Jerusalem crosses. In a preferred embodiment, the shapes of the apertures and patches are geometrically congruent. A dual-band FSS, having apertures and corresponding patches in two different sizes and spacings, can transmit two separate frequency bands.

Abstract: A non-rotatable radar antenna installation for aircraft for providing 360.degree. azimuthal scanning, which includes a generally triangular radome carried by the aircraft, and three substantially planar radar antennas arranged in a triangular planform within the radome. 360.degree. azimuthal coverage is achieved by the sequential side-to-side scanning of the three antennas. The planform area of the triangular radome and consequently the drag and weight penalty of the radome upon the aircraft is substantially less than equivalent radar antenna installations of circular configuration.

Abstract: The structure includes a ground plane and at least two stacked microstrip elements with each microstrip element comprising a conducting plane and a layer of dielectric material. The conducting planes and the intermediate dielectric layers are configured so that they resonate at closely spaced frequencies. Each conducting plane in the structure, except the top one, includes an opening which is large enough to permit sufficient electric field coupling to occur between the microstrip elements so that the individual response characteristics of the conducting planes merge to form a broadband response characteristic. The antenna of the present invention thus has a substantially improved bandwidth over prior art microstrip antennas.