Abstract: A multibeam hemispherical X-band array inserts nulls at horizontal and near horizontal angles to suppress interfering signals, without degrading authentic signals arriving at other angles. The multibeam hemispherical array includes three annular (360) rows of antenna elements, each row having 64 elements. Elements of the first row, which have the smallest elevation angle, have pairs of circular patches coupled with a phase delay line. Each pair of circular patches is spaced apart from and aligned with two pairs of similarly shaped (circular) and sized parasitic directors. The spacing between driven patches of adjacent elements in a row is about equal to one half of the wavelength of the radiated wave. The array fits within a conventional 24-inch diameter marine radome.

Abstract: A low profile patch antenna surface mounted to a metal base produces superior gain in horizontal directions. A dielectric spacer and matching circuit are sandwiched between a thin circular patch radiator and an opposite ground plate, with the matching circuit between the spacer and ground plate and electrically coupled to the ground plate and radiator. The matching circuit increases antenna efficiency and bandwidth by attaining the best possible energy transfer between a transceiver and the antenna, taking into account impedance mismatch, component losses, and losses in the antenna structure.

Abstract: A low profile antenna assembly for an aircraft radome includes a reflector, a feed with a stacked array of septum polarizers, a mount, and a bracket. The feed, which includes bandpass and low pass filters, and broadwall branchline couplers, and the stacked array of septum polarizers, together determine polarization of the waves, attenuating unwanted signals and illuminating the entire reflector. The reflector comprises a portion of a parabolic reflector.

Abstract: A low profile antenna assembly for an aircraft radome includes a reflector, a feed with a stacked array of septum polarizers, a mount, and a bracket. The feed, which includes bandpass and low pass filters, and broadwall branchline couplers, and the stacked array of septum polarizers, together determine polarization of the waves, attenuating unwanted signals and illuminating the entire reflector. The reflector comprises a portion of a parabolic reflector.