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: 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.