Abstract: A multi-spectral seeker system for detecting radiation in the infrared (IR) band and a plurality of radio frequency (RF) bands suitable for use in a guided missile is disclosed. The IR and RF seekers are coaxially integrated on a single gimbaled platform and share a common aperture without significant performance degradation. In the preferred embodiment, the IR seeker uses a Cassegrainian reflector assembly with surfaces reflective to IR but transparent to RF signals. The first RF seeker uses a resonant dichroic reflector antenna which is transparent to RF signals at frequencies no closer than 0.5 octaves from the dichroic reflector system operating frequency. The second RF seeker may use any suitable RF antenna system although a planar-array of multi-mode spiral antennas or a standard flat plate slotted array are preferred. The second RF seeker may operate in an active, semi-active, or passive mode.

Abstract: A low-profile full aperture traveling wave monopulse antenna assembly including a circular faceplate having a plurality of parallel rows of radiating apertures formed therethrough, a circular backplate having a pair of feed openings each extending across the backplate on opposite sides of and parallel to a centrally located chord perpendicular in orientation to the rows of radiating apertures, a circular backplate mounted between and spaced apart from the faceplate and the backplate by a plurality of walls forming a plurality of parallel waveguide channels therein, a pair of feed waveguides each mounted adjacent the backplate above a different feed opening and each electromagnetically coupled to opposite ends of the waveguide channels, and a monopulse comparator network mounted adjacent the backplate and coupled to the pair of feed waveguides.

Abstract: An antenna system having first and second arrays of radiating members, first and second sets of corresponding bifurcated members and two pairs of feed members. The radiating members of the first and second arrays each have a near end and a far end and a linear portion therebetween with radiating slots formed therein. The linear portions of the radiating members are interleaved in a planar spaced parallel relationship. Each bifurcated member has a unitary portion and a bifurcated portion with the bifurcated portion having a pair of coupling ends. Each bifurcated member is coupled at its unitary portion to the near end of a different radiating member of its corresponding array and also coupled at its coupling ends to a different feed member of its corresponding pair of feed members. The antenna system further includes a monopulse comparator coupled to the input ends of the first and second pairs of feed members for operation as an amplitude comparison monopulse antenna.

Abstract: A method for making a metalized dichroic parabolic lens reflector for multi-frequency antenna system applications. The reflector is prepared by depositing an etchable conductive metallic layer upon a parabolic work surface of a male mandrel. The metallic layer is adhered to a parabolic support surface of a substrate formed of a low dielectric constant material. The mandrel is separated from the metallic with the metallic layer remaining bonded to the support surface. Photoresist imaging and chemical etching techniques are used to form a dipole grid pattern in the metallic layer.

Abstract: An antenna feed structure for use with a parabolic reflector in amplitude-comparison monopulse radar applications employs a dedicated transmit feed centered within a four-port receive array of conventional element spacing to eliminate the need for a circulator or other transmit/receive device while retaining satisfactory receive array performance. Isolation pins placed around the transmit port act to decouple it from the receive ports, and a double waveguide run to the transmit port reduces uneven heating and related phase imbalance in adjacent receive waveguide runs.

Abstract: A dual mode target seeking system for airborne vehicles which operates under two different frequencies simultaneously includes a radio frequency antenna comprising a slotted plate defining a ground plane with an image plate positioned in front of the ground plane at a distance chosen such that multiple reflected rays are in phase with each other and with waves incident on the image plate. The slotted plate and image plate have aligned central openings through which an electro-optical system for operating under a chosen electro-optical frequency range, for example under infrared frequencies, projects. The electro-optical system includes a detector unit positioned behind the antenna and a focussing system for directing incoming electro-optical radiation into the detector unit. The focussing system includes first and second lenses mounted in the openings in the image plate and slotted plate, respectively.