Abstract: A radiator element includes a pair of substrates each having a transition section and a feed surface, each of the substrates is spaced apart from one another. The radiator element further includes a balanced symmetrical feed having a pair of radio frequency (RF) feed lines disposed adjacent to and electromagnetically coupled to the feed surface of one of a corresponding one of the pair of transition sections, and the pair of radio frequency feed lines forms a signal null point adjacent the transition sections.

Abstract: A radiator element includes a pair of substrates each having a transition section and a feed surface, each of the substrates is spaced apart from one another. The radiator element further includes a balanced symmetrical feed having a pair of radio frequency (RF) feed lines disposed adjacent to and electromagnetically coupled to the feed surface of one of a corresponding one of the pair of transition sections, and the pair of radio frequency feed lines forms a signal null point adjacent the transition sections.

Abstract: A waveguide feed structure having a coaxial transmission line. A conductive, planar septum is disposed in, and along a diameter of, the transmission line. A feed port is electrically coupled to the transmission line. The septum has a rear portion disposed proximate the feed port, such rear portion of the septum extending between the inner conductor and the outer conductor. The feed port and the rear portion of the septum are arranged to establish an electric field in the transmission line between the inner conductor and the outer conductor with a component substantially TE11 mode along a direction perpendicular to the planar septum. A forward portion of the septum is asymmetrically disposed with respect to said diameter in order to provide a gap between the inner conductor and the outer conductor, such gap establishing an electric field component within the transmission line having a TE11 component along said diameter of the transmission line parallel to the plane of the septum.

Abstract: A radiator includes a waveguide having an aperture and a patch antenna disposed in the aperture. In one embodiment, an antenna includes an array of waveguide antenna elements, each element having a cavity, and an array of patch antenna elements including an upper patch element and a lower patch element disposed in the cavity.

Abstract: A radiator includes a waveguide having an aperture and a patch antenna disposed in the aperture. In one embodiment, an antenna includes an array of waveguide antenna elements, each element having a cavity, and an array of patch antenna elements including an upper patch element and a lower patch element disposed in the cavity.

Abstract: A waveguide feed structure having a coaxial transmission line. A conductive, planar septum is disposed in, and along a diameter of, the transmission line. A feed port is electrically coupled to the transmission line. The septum has a rear portion disposed proximate the feed port, such rear portion of the septum extending between the inner conductor and the outer conductor. The feed port and the rear portion of the septum are arranged to establish an electric field in the transmission line between the inner conductor and the outer conductor with a component substantially TE11 mode along a direction perpendicular to the planar septum. A forward portion of the septum is asymmetrically disposed with respect to said diameter in order to provide a gap between the inner conductor and the outer conductor, such gap establishing an electric field component within the transmission line having a TE11 component along said diameter of the transmission line parallel to the plane of the septum.

Abstract: A communications card having an antenna assembly providing polarization diversity for use with a portable computer is provided. The antenna assembly comprises two folded antennas, which may be dipoles or slot radiators, that are disposed orthogonally to one another to provide polarization diversity. Signals are carried to and from the antenna by microstrip feed lines. The microstrip lines are placed off center along each antenna slot to establish an acceptable impedance match for the antenna. The feed lines are coupled to the communications card by way of coaxial cables. The antenna assembly is coupled with the communications card in a hinged arrangement thus allowing for spatial redirection of the antenna, if desired.

Abstract: A single radiating structure with an integrated mode transducer that produces near-ideal radiation characteristics at two frequency bands. The dual band feed consists of three main sections: feed waveguide, mode transducer and corrugated horn. The feed waveguide consists of two concentric, circular waveguides that are excited in the TE.sub.11 coaxial and circular waveguide modes for the low and high bands, respectively. The mode transducer, which is critical to the performance of the feed, provides a single mode, low return loss transition, for both bands, between the feed waveguide and the corrugated horn. This is achieved by converting the TE.sub.11 circular waveguide modes into the fundamental hybrid, HE.sub.11, mode of the corrugated horn. The corrugated horn, which is a stepped-slot configuration, is designed to achieve a smooth transition from the mode transducer and to produce the desired radiation characteristics at both frequency bands.

Abstract: An antenna includes a substrate having a first surface with a ground plane disposed thereover and having a second surface with a first plurality of strip conductors disposed along a first longitudinal axis thereof. A feed circuit has a first port coupled to an input port of the antenna and a plurality of second ports, each of which is coupled to one of the first plurality of strip conductors. A radome has a first surface disposed over and spaced a predetermined distance from the second surface of the substrate. A second plurality of strip conductors are disposed on the first surface of the radome above corresponding ones of the first plurality of strip conductors on the second surface of the substrate.

Abstract: A phased array radar antenna uses time-steering subarray notch weightings to produce a wideband notch in the direction of interference for Electronic-Counter-Measure (ECM) interference suppression. A predetermined set of subarray notch weightings, each set being identical for each subarray, is stored in controllers each of which is coupled to a plurality of phase shifters and attenuators for feeding radiating elements of the antenna. Interference suppressors operate from a plurality of controllers to produce a subarray pattern having a notch in the direction of interference. Beamformers then combine outputs of all time-steering subarrays in the antenna so as to produce an antenna pattern having a wideband notch in the direction of interference.

Abstract: An improved means of decorrelating phase quantization errors in a phased array radar antenna using digital randomization at each of the array elements to reduce peak steering erorrs and to reduce peak sidelobe levels of the antenna. A random phase adjust term is provided to each of the array's antenna elements which comprises a distributed controller (DC) co-located with a digital phase shifter. The distributed controllers are each programmed with a random phase adjust term which represents a phase shift adjustment statistically independent from element to element. The random phase adjust term is stored in a memory located in each disbtributed controller. The distributed controller drives each element's digitally controlled phase shifter in response to a beam steering command received over a serial line. The performance improvement achieved with this decorrelation method is equivalent to that obtained by using more expensive phase shifters and adding costly randomized cables in the path to each element.

Abstract: A network having a plurality of network ports includes a plurality of substantially identical, independent components, each one thereof having a plurality of ports, the degree of coupling among the ports of each component being characterized by a predetermined scattering coefficient matrix. A plurality of feed networks is included, each one having: a first port corresponding to one of the plurality of network ports; and, a plurality of second ports each one being coupled to a corresponding one of the plurality of ports of each one of the plurality of components, the degree of coupling among the first port and the plurality of second ports of each of the feed networks being characterized by a predetermined scattering coefficient matrix. The plurality of feed networks and the coupling thereof to the components characterize the network with a scattering coefficient matrix, relating the coupling among the network ports, different from the scattering coefficient matrix characterizing each one of the components.