Abstract: 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.

Abstract: 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.

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: 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.

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.