Abstract: A multimode horn used to feed an antenna includes a generally conical wall for transmitting and/or receiving an electromagnetic signal there through. The wall flares radially outwardly from a throat section to an aperture and defines an internal surface having a plurality of discontinuities formed thereon and made out of electrically conductive material. The geometry of the discontinuities are configured and sized for altering the higher order mode content of the signal to achieve a balance between a plurality of performance parameters of the antenna over at least one pre-determined frequency range of the signal. The discontinuities are selected from the group consisting of local smooth profile, step, corrugation and choke.

Abstract: A dual frequency array antenna comprises an upper layer including an array of antennas operating at a first frequency, a first ground layer disposed below the upper layer at a predetermined distance and a dielectric material disposed between the first ground layer and the upper layer. An array of slot radiator apertures are provided in the first ground layer. The apertures are spaced from the array of antennas and radiate at a second frequency. An array of feed lines is disposed at a predetermined distance below the first ground layer with one of the feed lines below each one of the apertures. A second ground plane layer is disposed at a predetermined distance below the array of feed lines. The two frequencies are, for example, from two distinct microwave bands.

Abstract: The reflector consists of a ground plane, enclosed in a ground plane frame, and a phasing plane, enclosed in a phasing plane frame. Spacers maintain the planes in connected, spaced relationship. The phasing plane includes a plurality of reactive elements sensitive to different frequencies in the bandwidth of the reflector. Thus, an E-M wave directed at the reflector is reflected to the angle of the received wave.