Raytheon Company

US Government As Represented by the Secretary of the Army

Jerome D Hanfling

Jack J Schuss

Kaichiang Chang

Jeffrey C Upton

Richard L O'Shea

Michael J Collins

Alfred J Appelbaum

Karl L Mengoli

A low array antenna having transmit/receive (T/R) modules, which contain a digitally-controlled variable attenuator, for each of the two polarizations (horizontal and vertical). The array has a cylindrically curved surface which closely conforms to the shape of the fuselage of an airborne vehicle or another structure. Each polarization feeds into an elevation beamformer apparatus which provides both a uniform taper and a Bayliss/Taylor taper. As the beam is scanned in elevation, the amplitude taper is adjusted via the variable attenuator to control the taper of a sum pattern and thereby achieve low sidelobe far field sum patterns. The same attenuators that are used for the sum pattern also feed a difference network. The T/R module attenuators are set to yield the desired low sidelobe sum illumination for a desired elevation scan angle. As the array is steered in elevation, the Bayliss difference taper is distorted since the fixed elevation beamformer cannot adjust the difference pattern for the new scan angle. A T/R module is provided at each column of the array to combine the distorted Bayliss difference pattern with the compensated Taylor sum pattern output. This combining permits the distorted Bayliss array illumination to be resymmetrized thereby producing a high quality, low sidelobe, compensated Bayliss far field pattern. This apparatus provides for complete compensation of both sum and difference patterns with only a single attenuator at each element of the array and a simple monopulse feed network.

Scan compensation for array antenna on a curved surface

A low-profile patch radiator for use in an array antenna has a multilayer structure which includes a double-tuned impedance matching network and balun and a coaxial feed for linear polarization of the radiated waves. A second embodiment further includes a second double-tuned impedance matching network and balun and a second coaxial feed for dual polarization operation. The matching networks/baluns, which comprise microstrip circuits on Duroid substrates, increase the frequency bandwidth of the patch radiator.

Patch radiator element with microstrip balian circuit providing

A space fed antenna system is adapted to correct for beam pointing (squint) errors and collimation errors caused by frequency variations of the R.F. energy radiated by the antenna system. A subarray of radiating elements is spatially positioned between an electronic lens and the focal point of said lens. The subarray radiates R.F. energy with a spherical wavefront for illuminating the electronic lens, such spherical wavefront having a focal point coincident with the focal point of the electronic lens. A programmer is provided which controls the electronic lens to collimate and direct the R.F. energy from the subarray. A corporate feed is provided which couples to a plurality of phase shifters which feeds corresponding time delay units, which in turn feeds corresponding radiating elements in the subarray. The phase shifters, responsive to the programmer, provide the spherical wavefront to the R.F. energy radiated by radiating elements in the subarray. The time delay units, also responsive to the programmer, vary the phase of the R.F. energy radiated by said elements to correct the squint and collimation errors.

Space fed antenna system with squint error correction

An improved IFF antenna arrangement is shown to comprise two linear arrays, each one of the arrays being made up of a plurality of similar cavity-backed radiating slots fed by a stripline feed. The impedance of each radiating slot is matched, at two different operating frequencies, to the impedance of a combination of the impedances of the corresponding cavity and stripline feed.

IFF antenna arrangement

A means for retaining radar elements in a structural configuration for a sed array. The elements are inserted in connectors and are held between two cap plates. The array face and retention configuration is to satisfy electrical and mechanical requirements in order to minimize surface-wave propagation and to predict scanning performance.

Growing community of inventors

Framingham, MA, United States of America

Jerome D Hanfling