Hughes Missile Systems Company

General Dynamics Corp., Pomona Division

Henry T Killackey

John T Branigan

William E Bullen

Richard M Pietrasz

Joseph M Gailliot, Jr

Dean W Collins

Julia N Martin

William E Salmond

A dual frequency antenna and radome system, including a dual frequency antenna system for operation at a first, higher frequency band and at a second lower frequency band. The antenna system includes a first antenna operable at the first frequency band and a second antenna operable at the second frequency band. The first and second antenna systems are orthogonally polarized. A radome is tuned for dual frequency operation, and includes a dielectric wall having a thickness equal to one-half wavelength at a frequency in the first frequency band. The radome further includes a grid of monopole elements formed on a surface of the dielectric wall orthogonal to the first antenna to tune the radome to efficient operation at the second frequency band.

Dual frequency radome

The target seeker system includes two radio frequency antennas consisting of two sets of radio frequency selective annular slot patch excited radiator receiver elements, one set for K-band energy, the other for X-band energy, sharing a common ground plane. The radio frequency antennas have a single multi-band image plate consisting of resonant dichroic surfaces which will selectively reflect X- and K-band energy. An image plate is formed with conductive patterns on each side of a low dielectric material. The reflective pattern acts as a quarter wavelength thick plate at the operating frequency. The top of the image plate which has X-band reflectors is spaced at one-half of the desired X-band wavelength above the ground plane and the K-band reflector on the bottom of the image plate is spaced at one-half of the desired K-band wavelength. The thickness of the image plate is adjusted to provide the appropriate relative spacing between the X-band reflecting surface on the top and the K-band reflecting surface on the bottom.

Annular slot patch excited array

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. The IR seeker means and both RF seeker means together provide coaxial seeking in a single aperture covering three frequency bands without significant loss of performance in the RF antenna and IR sensor. The material on which the parabolic reflector is formed is tapered in thickness as a function of radius to eliminate phase delays introduced by the curvature as seen by the second RF seeker.

Multi-spectral seeker antenna

The described embodiments of the present invention provide a high-gain antenna while allowing for the inclusion of devices within the antenna array. In one embodiment of the invention an array of receiver/transmitter elements is positioned in a pan-like reflector base. The elements are positioned one-quarter of a wavelength from the surface of the base. The wavelength is the wavelength of the chosen frequency of transmission or reception of the antenna. A partially reflective plate is positioned one-half wavelength from the base and thus one quarter wavelength from the elements. Reflective disks are also positioned one-half wavelength above the base and are positioned directly above the elements. The disks create a resonant cavity around the elements for waves of the chosen frequency arriving from near normal to the plane of the base or being emanated from the elements at a normal or near-normal angle. The partially reflective plate extends this resonant area spatially from the element. Because of the extending effect, wider dispersion between array elements may be utilized, wider dispersion between array elements may be utilized while maintaining good gain and side-lobe characteristics. In another embodiment the wider spatial characteristics allow the use of an irregular array. This array allows space for electro-optical devices in the array itself. Another embodiment includes an optically transparent portion of the base. This transparent portion is treated so the surface of it is conductive and thus electromagnetically reflective. The transparent portion allows for optical transmission to sensors located beneath the transparent portion.

Image plate/short backfire antenna

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.

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Covina, CA, United States of America

Henry T Killackey