US 4,792,805 A · Multifunction active array

Abstract

A multifunction active array system is disclosed, wherein the array aperture may be partitioned into a plurality of arbitrary subapertures. The array system includes N radiative elements, each coupled to a corresponding active module. Each module is in turn connected to an aperture partition selector, which includes an M-way power divider/combiner device, having a module port and M device ports. Each device port is coupled through an RF switch to a partition port of the device. M N-way manifolds are provided, having N manifold ports coupled to a respective one of said partition ports of each selector. The manifolds are coupled to a receiver and an excitation source. Each partition may be formed by the desired connection of a particular module to a manifold by the respective positions of the RF switches. The array system provides the capabilities of partitioning the array into M or less subapertures to simultaneously generate sum patterns, difference patterns, guard patterns, and adaptive nullings. The partitions on receive and transmit are independent, and they may differ in any arbitrary manner. The subapertures may overlap.

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Claims20

Dependent claims

An array system for providing a plurality of array subapertures, comprising:

an array of N spaced radiative elements forming a radiative aperture;
N aperture partitioning selector devices respectively coupled one to a respective radiative element for dividing said radiative aperture into M or fewer subapertures, comprising:
an M-way power divider device having M device ports and a radiative element port coupled to said radiative element, said divider device adapted to divide the power of signals received at said radiative element into M component signals of substantially equal power at said device ports;
and
means for selectively connecting said respective device ports of said power divider device to a corresponding partition port of said selector device;
M manifold apparatus having N manifold ports, each of said ports respectively connected to a corresponding partition port of said N aperture partitioning selectors, said manifold apparatus comprising means for combining the respective component signals at said corresponding partition ports of said N selector devices and providing a respective subaperture signal at an output port of each of said M manifold apparatus;
an array system controller coupled to said selector devices for controlling said means for selectively connecting said device ports to control the partitioning of said aperture into M or fewer subapertures, each subaperture comprising the radiative elements selectively connected to said respective manifold apparatus;
and
a receiver responsive to said M subaperture signals to provide a selected partitioned aperture function.

6 more elements

An active array system for providing a plurality of array subapertures, comprising:

an array of N spaced radiative elements forming a radiative aperture;
N active modules respectively coupled one to each radiative element, said modules comprising a receive channel comprising a low noise amplifier coupled to said corresponding radiative element for amplifying signals received at said corresponding radiative elements and providing said amplified receive signals at a module selector port;
N aperture partitioning selector devices respectively coupled one to a selector port of each module for dividing said radiative aperture into M or fewer subapertures, comprising:
an M-way power divider device having M device ports and a module port coupled to said selector port of said module, said divider device adapted to divide the power of said amplified receive signals at said module port into M component signals of substantially equal power at said device ports;
and
means for selectively connecting said respective device ports of said power divider device to a corresponding partition port of said selector;
M manifold apparatus having N manifold ports, each of said ports respectively connected to a corresponding partition port of said N aperture partitioning selectors, said manifold apparatus comprising means for combining the respective component signals at said corresponding partition ports of said N aperture partitioning selectors and providing a respective subaperture signal at an output port of each of said M manifold apparatus;
an array system controller coupled to said aperture partition selectors for controlling said means for selectively connecting said device ports to control the partitioning of said aperture into M or fewer subapertures, each subaperture comprising the radiative elements and associated modules connected to said respective manifold apparatus;
and
a receiver responsive to said M subaperture signals to provide a selected partitioned aperture function.

7 more elements

A multifunction active array system for providing a plurality of arbitrary array subapertures, comprising:

an array of N spaced radiative elements forming a radiative aperture;
N active modules respectively coupled one to each radiative element, said module comprising a transmit channel comprising a transmit amplifier for amplifying excitation signals and a receive channel comprising a low noise amplifier for amplifying signals received at said corresponding radiative element, and means for coupling either said transmit channel or said receive channel to said radiative element;
an excitation signal source for generating one or more excitation signals;
a plurality of aperture partitioning selectors coupled one to a selector port of each module for dividing said radiative aperture into M or fewer subapertures, each selector comprising:
an M-way power divider/combiner device having M device ports and a module port coupled to said selector port of said corresponding module;
and
means for selectively connecting said respective device ports of said power divider/combiner device to a corresponding partition port of said selector;
M manifold apparatus having N manifold ports, each of said ports respectively connected to a corresponding partition port of said N aperture partitioning selectors, said manifold apparatus arranged to combine signals at said partition ports of the N modules and provide a combined subaperture signal at a combiner output of said manifold apparatus in a receive mode, said manifold apparatus being further arranged to divide an excitation input signal into N excitation module signals at said N ports of said manifold apparatus in a transmit mode;
and
an array system controller coupled to said aperture partition selector and said modules for controlling said means for selectively connecting said device ports to control the partitioning of said aperture into M or fewer subapertures and to select either the receive channel or the transmit channel of said module.

7 more elements

Dependencies are inferred from the claim text.

Description4,585 words

Summary574 words

#The invention relates to techniques for electronically varying the partitioning of planar arrays or phase scanned arrays into sub-arrays or subapertures.

#In many airborne radar modes, in particular the terrain following and terrain avoidance modes, difference patterns stabilized with respect to the horizon are required. The technique generally used to generate sum and difference patterns in gimballed planar arrays or phased scanned arrays is to partition the array into quadrants with a separate output for each quadrant. The appropriate quadrant outputs are summed or differenced to provide a sum pattern and two difference patterns. The two difference patterns provide tracking error signals referenced to the antenna.

#Conventional solutions to the problem of providing roll stabilized sum and difference patterns in airborne radars include providing a third gimbal or implementing rather cumbersome and not entirely satisfactory signal processing to derive roll stabilized tracking outputs. The roll gimbal technique is probably not feasible for active array systems of sufficient size to require liquid cooling. An alternative to the signal processing approach is needed.

Brief description of the drawings5 figures

#These and other features and advantages of the present invention will become more apparent from the following detailed description of an exemplary embodiment thereof, as illustrated in the accompanying drawings, in which:

#FIG. 1 is a simplified functional block diagram, for M=3, of a multifunction active array system embodying the invention.

#FIG. 2 is a functional diagram illustrative of an array system as in FIG. 1 with a circular aperture, showing the division of the aperture into four quadrants for generating simultaneous sum, azimuth difference, and elevation difference patterns.

Detailed description3,842 words

#Referring now to FIG. 1, a block diagram of a multifunction active array system embodying the invention is disclosed. As will be understood by those skilled in the art, the array comprises a plurality of radiative elements 15, each coupled to a corresponding active module 20. For clarity, only the "i"th element 15 and module 20 are shown in FIG. 1, where i is an index varying from 1 to N, and N represents the total number of modules. Each of the modules comprising the array is identical to the universal module 20 of FIG. 1.

#Module 20 comprises a beam steering phase shifter 32 and a variable RF attenuator 28. These two devices may be connected either to the transmit channel comprising transmit amplifier 24 or to the receive channel comprising low noise amplifier 26 by RF switch 30. RF switch 22 connects either the receive channel or the transmit channel to the radiative element 15. The RF switches 22 and 30 are controlled by the array controller 94 to select either the module transmit channel when an excitation signal is provided to the module 20 or the module receive channel when the module 20 is selected to provide an amplified version of signals incident on the radiative element 15. In operation, the RF switches 22 and 30 are both either in the transmit "T" position or in the receive "R" position. The functions of these switches could alternatively be accomplished by RF circulator devices, well known to those skilled in the art.

#The beam steering phase shifter 32 preferably is digitally controlled by controller 94, and introduces the phase shift necessary to steer the aperture beam in the desired direction, as is well known to those skilled in the art.

Facts

Application

07/043,406Filed 28 Apr 1987

Granted

20 Dec 1988

Term ended

28 Apr 2007

Estimated · how

Pre-1995 term; greater of 17 years from grant or 20 years from filing when eligible. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification4 codes

H01Q 3/24
Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna…
H01Q 3/26
Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna…
H01Q 25/00
Antennas or antenna systems providing at least two radiating patterns
H01Q
Antennas, i.e. radio aerials

Multifunction active array

Life of this patent

Multifunction active array

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims20

Description4,585 words

Drawings

Classification4 codes

Life of this patent

Description4,585 words