United States of America As Represented by the Secretary of the Air Force

University of Massachusetts

Mcdonnell Douglas Corporation

Robert J Mailloux

Peter R Franchi

Allan C Schell

Harvey E Tobin

Thomas M Roberts

Scott G Santarelli

Methods for producing wide-band planar array antenna designs and antenna corresponding thereto.

Method and apparatus for wideband planar arrays implemented with a polyomino subarray architecture

A constrained feed can enable a phased array to be fed from a number of subarray ports while maintaining good sidelobe control. The invention pertains to using constrained feed networks, like Rotman lenses, Butler matrices and waveguide networks instead of a single space feed, to produce these subarrays. The formed subarrays are partially overlapped, and this is required to develop good sidelobe control. The invention solves the problem of having high sidelobes when an array is fed by contiguous, uniformly illuminated subarrays and so allows optical time delay, digital time delay and limited field of view scanning with a constrained network while maintaining low sidelobe radiation.

Constrained feed techniques for phased array subarrays

A method to measure the far field antenna pattern of an experimental antenna on a smaller range than conventionally used. The basic innovation of the present invention is that the implementation is moved in straight line, toward or away from the antenna under test (AUT), and the measurements are taken while the AUT is rotated about its phase center in a manner that is synchronized with the radial probe.

Linear near field test facility and process

A technique that enables array error correction by replacing the signals from failed elements with processed signals derived from operating elements. The procedure is shown to be useful in a multisignal environment. Expressions are derived that give the signal to noise ratio of arrays with any number of failed elements with replaced signals. These relations are used to investigate the counterintuitive limiting case in which all the signals of an array are replaced by the reproduced signals.

Substitution procedure and apparatus for phased array error correction

Improved performance of an electronically scanned subarray antenna system is realized by tailoring the subarray pattern in a manner that reduces the undesirable effects of illumination truncation at the edge of the main array. This is accomplished by introducing variable attenuators into individual feed elements to effect an illumination intensity taper of the feed element array output. The improvement permits effective utilization of deterministic and adaptive nulling at both the main array and the subarray levels and further provides a system ability to scan over wide spatial angles with wide bandwidths and low sidelobes. The technique is adaptable to both space fed and constrained subarray antenna systems.

Subarray pattern control and null steering for subarray antenna systems

Sidelobe suppression and other beam transmission property manipulations in directional beam forming antennas is accomplished by means of a spatial filter. The filter geometry consists of a plurality of metallic gratings separated by air or other low dielectric constant dielectric substance. The filter is placed directly over the antenna radiating aperture and is encompassed by a tunnel structure of electromagnetic wave energy absorbing material. The shunt susceptance characteristics of the metallic gratings together with the integrating spacing distances are synthesized in a manner that effects full transmission of beam power in a selected beam direction while offering substantial rejection of it in other directions.

Metallic grating spatial filter for directional beam forming antenna

Sidelobe suppression in directional beam forming antennas is accomplished by means of a spatial filter. The filter geometry consists of flat layers of high dielectric constant dielectric separated by air or other low dielectric constant dielectric substance. The filter is placed directly over the antenna radiating aperture and its dielectric materials have dielectric constant and thickness values that effect full transmission of beam power in a selected beam direction and substantial rejection of it in other directions.

Layered dielectric filter for sidelobe suppression

High gain limited scan operation of phased array antennas is accomplished with microwave circuitry by appropriately coupling the array elements into sub-arrays and establishing a 90.degree. out of phase relationship between even and odd mode power at the aperture of each array element. Even and odd mode power from the feed circuit of each element is coupled to the feed circuit of each nearest adjacent element to form three element overlap subarrays in each plane of scan.

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Wayland, MA, United States of America

Robert J Mailloux