Abstract: A vertical array antenna is disclosed. The antenna includes a housing configured to be positioned above a ground plane and a plurality of antenna elements. Each antenna element produces an individual beam pattern. The antenna elements are attached to the housing at different distances from the location of the ground plane such that the amplitudes of the individual beam patterns of the respective antenna elements have local maxima at a common angle and frequency when the housing is positioned above the ground plane.

Abstract: An antenna system includes a reflector having a focal point, and a phased array having feed elements. Each feed element is disposed a same distance from the focal point of the reflector. A method for varying the beamwidth of an antenna system includes providing the antenna system with a reflector having a focal point and feed elements disposed a same distance from the focal point. The feed elements includes one or more inner feed elements and one or more outer feed elements. The method further includes adjusting relative amplitudes of the inner feed elements and the outer feed elements to adjust the beamwidth of the antenna system. An antenna system includes a parabolic reflector having a focal point, and a phased array having one or more inner feed elements and one or more outer feed elements. Each of the feed elements is disposed a same distance in wavelengths from the focal point, and is oriented towards the focal point.

Abstract: A spiral planar antenna includes more than two spiral arms. Each arm includes at least a portion that is coiled. The antenna may operate from approximately 50 MHz to upwards of several GHz within a payload space of only about 5.75 inches in diameter and less than one inch in height, with approximately 5 dBi or less of measured axial ratio. The broad frequency response in conjunction with a small space-profile improves space limitations and payload for deployable and non-deployable platforms while reducing opportunities for electromagnetic interference.

Abstract: An antenna system includes a reflector having a focal point, and a phased array having feed elements. Each feed element is disposed a same distance from the focal point of the reflector. A method for varying the beamwidth of an antenna system includes providing the antenna system with a reflector having a focal point and feed elements disposed a same distance from the focal point. The feed elements includes one or more inner feed elements and one or more outer feed elements. The method further includes adjusting relative amplitudes of the inner feed elements and the outer feed elements to adjust the beamwidth of the antenna system. An antenna system includes a parabolic reflector having a focal point, and a phased array having one or more inner feed elements and one or more outer feed elements. Each of the feed elements is disposed a same distance in wavelengths from the focal point, and is oriented towards the focal point.

Abstract: A ridged horn antenna that is designed to operate simultaneously in multiple modes with improved efficiency and higher gain. In one embodiment, the antenna has at least five ridges (e.g., eight ridges). Preferably, each ridge is independently fed by a feedline (e.g., coaxial cable). In order to match impedances better, the feedlines can be tapered from an uncoupled state to a highly coupled state. A beamforming network having a plurality of ports can be coupled to the feedlines. Preferably, the beamforming network is designed to provide multiple progressive phase relationships to the ridges through the coupled feedlines for simultaneous multiple operating modes.

Abstract: A spiral antenna system that is designed to have an increased upper frequency limit. The system includes a spiral antenna element having a feed end, and a helical antenna element having a helical portion electrically interconnected with the feed end of the spiral antenna element. In one embodiment, the helical antenna element comprises a coaxial cable having a portion of the outer conductor removed (e.g., tapered). For example, the helical antenna element could comprise a portion of the feedline that follows a substantially helical path. Preferably, the spiral antenna element defines a spiral axis, and the helical antenna element defines a helical axis substantially aligned with the spiral axis. The helical antenna element can be spaced from the helical axis a distance less than or equal to the radial distance of the feed end of the spiral antenna.