Abstract: Surface structures attached to a support member for reducing coupling between two antennas carried by the support member or for reducing the side lobes of a horn antenna, the structures consisting of thin metallic portions or strips partially covering dielectric material in layer form and the complete supporting structure being secured to the support member in order to present to an electromagnetic wave passing over the surface of the surface structure a surface impedance which is capacitive in nature in order to repel the electromagnetic wave away from the surface.

Abstract: A construction for reducing the side lobe energy emitted from antennas, particularly horn antennas, and thereby attenuating unwanted coupling with adjacent antennas, the construction utilizes a continuous helical coil located on the interior surface of the antenna horn in order to progressively delay the current flowing along the horn wall by causing the current to follow a longer path than that portion of the wave which propagates well away from the wall, the number of coil turns being selected to cause the portion of the E plane which arrives at the horn aperture to be out of phase by approximately one-half wave length with the portion of the E plane propagated away from the horn wall so that it will cancel the E plane energy at the aperture.