International Telephone and Telegraph Corporation

Itt Corporation

Itt Gilfillan, a Division of Itt Corporation

Bradford E Kruger

John C Parr

Walter J Noble

An active aperture radar antenna includes a plurality of T/R modules and a plurality of radiators, each being supported upon an intermediate support structure disposed therebetween for holding the modules and the radiators at predetermined positions relative to one another. The support structure is a composite structure formed by ribbed support housings and joined by a central plate. The ribs in the support housings defining channels for accommodating coolant tubes and for stiffening the structure. The T/R modules contact the support structure proximate the transmit amplifier chains for enhanced cooling. The radiator array is formed upon a circuit board, is independent of the T/R modules and is disposed upon an opposing surface of the support structure. The T/R modules can be removed and replaced without disturbing any radiators or their relative coplanarity.

Support apparatus for an active aperture radar antenna

A transmit/receive system for electromagnetic radiation, particularly radar, employs an array of active transmit/receive (T/R) modules. Only a portion of the modules are actuated to transmit or receive signals at any given time. Input transmit power is supplied to all modules, but only the selected portion of modules actually amplify their inputs. The power loss is thus kept small because the amplified signal power far outweighs the lost input power. This approach makes possible a monopulse signal routing scheme that minimizes the number of switches used and their accompanying reliability problems. Transmit and receive signals are routed through sum-and-difference circuits and respective sectors of the T/R modules such that during RECEIVE no switches are necessary to acquire a monopulse sum (.SIGMA.) signal, and only a single switch is required to acquire a monopulse difference (.DELTA.) signal. Similarly, no switching of module inputs is required during TRANSMIT.

Directional transmit/receive system for electromagnetic radiation with

A shipboard search radar in which an antenna beam is stepped up and down in elevation to keep the beam pointed approximately toward the horizon even though the ship may be rolling and/or pitching.

Horizon stabilized antenna beam for shipboard radar

An electro-optical arrangement for transmitting signal data as modulated light energy across a rotating annular interface. The modulated light beams according to the system are projected axially within an annular cavity and thence outward through a redundant window arrangement. Another annular member rotatable with respect to the first one includes a plurality of closer-spaced but narrower second windows and a light-to-electric transducer associated with each second window. The spacing of the second windows is such that there is always light communication between the first and second window groups. The system is particularly adapted to digital modulation of the light energy.

Rotary annular signal data coupler

An annular rotary RF coupler for installation about a vertical support structure, such as the mast of a ship. Two annuli are divided into circumferential increments providing a cellular structure of individual waveguide cross-sections. A lower annulus (stator) remains fixed, the individual waveguide sections therein being fed from a power-divided, equal-phase, feed configuration. The oppositely facing upper annulus (rotor) rotates with respect to the lower one about the common mechanical center of rotation of a mechanically rotating antenna system. Connection to the rotating waveguide sections may be through power combiner/divider means, or individual subarrays may be discretely connected to one or more waveguide sections in the rotating annulus. For power tapering across an antenna array aperture, the waveguide section dimensions in the circumferential direction within the rotating annulus are appropriately tailored. A single enlarged stator cell is employed to accept the residual energy in the power distribution transmission line, eliminating the need for a termination load and the corresponding power loss.

Lossless annular rotary RF coupler

An annular rotary RF coupler for installation about a vertical support structure, particularly the mast of a ship. Two annular volumes are regularly divided into circumferential increments providing a cellular structure of individual waveguide cross-sections. A first annulus (stator) remains fixed, the individual waveguide sections therein being fed in equal phase from individual solid-state transmit/receive modules. The oppositely facing annulus (rotor) rotates with respect to the first annulus about the common mechanical center of rotation both share with a mechanically rotating antenna system. Connection to the rotating waveguide sections may be through power combiner/divider means (more than one rotor cell per antenna element or subarray), or individual antenna elements or subarrays may be discretely connected to corresponding waveguide sections in the rotor. For power tapering across the antenna aperture, the waveguide (cell) section dimensions in the circumferential direction within the rotating annulus may be appropriately tailored.

Around-the-mast rotary coupler with individual power module excitation

An electronic two-dimensional scanning array system with a two-dimensional interferometer array arrangement associated therewith is disclosed. The scanning array is used for transmitting a pencil beam, and the interferometer arrays are employed in receiving, array signal processing also being employed. The azimuth interferometer array consists of two sub-arrays, one on each side of the scanning transmitting array. The elevation interferometer array is likewise divided into two sub-arrays, one across the top and the other across the bottom of the scanning transmitting planar array. Accordingly, null responses in azimuth and elevation are provided. Phasors, which may be controlled by tracking functions, steer the center and nulls of the interferometer receive beam together in such a manner that the maximum improvement of the ratio of array-signal-process received target power to received power from an interfering source angularly separated from the interferometer center beam is achieved.

Adaptive two-dimensional null forming receiving antenna system

An antenna array consists of one or more slotted-waveguide, linear subarrays. Slots for radiation are cut in both narrow walls of each such waveguides, and PIN diodes across the slots are selectably forward and backward biased to effectively open the slots along one waveguide narrow wall while the others are closed and, alternatively, vice verse.

Edge slotted waveguide antenna array with selectable radiation direction

A sequential-lobing, radar, tracking device, particularly adapted to radars which scan mechanically in the azimuth plane and which have frequency-phase scan in addition. The phase scan operates to displace the beam in the vertical or elevation plane substantially normal to the plane of mechanical scan. Frequency scan provides a form of scan vernier and provides at least a substantial scan component in the direction of mechanical scan. The frequency scan is programmed to employ the time delay introduced between two vernier azimuth beam pair positions by the mechanical scan in azimuth, so that azimuth measurements, i.e., as between beams which tend to bracket a target, are made at the same transmitted frequencies. The azimuth measurement is therefore independent of frequency scintillation effects resulting from the unpredictable variation of radar target cross-section as a function of frequency.

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Woodland Hills, CA, United States of America

Bradford E Kruger