TECHNOLOGY AREAS: Sensors, Electronics, Battlespace

ACQUISITION PROGRAM: PMA-231, E-2D Advanced Hawkeye

OBJECTIVE: Utilizing advanced component technology, innovative optimization algorithms and design concepts, develop high-efficiency, multi-octave antenna array beamformer systems capable of adaptively compensating for significant dissimilarities in the on-aircraft array embedded element patterns.

DESCRIPTION: Antenna array beamformer designs typically assume that the array elements are isotropic radiators operating in free space in the absence of mutual coupling. The desired monopulse gain and sidelobe performance of an array over specified scan angles can be achieved with a predetermined fixed amplitude taper and stepped phase adjustments. Once the array is on the aircraft, its radiation pattern may change because of interactions with the radome structure, the airframe, and other nearby antennas. This has a detrimental effect on array radiation pattern. It is, therefore, necessary to account for the environment in which the antenna array is placed.

Providing complete amplitude and phase control at each element would appear to be the obvious solution. However, power loss in conventional amplitude and phase control beamformers make this solution impractical. To be practical, advanced low loss power dividers and phase shifters as well as wideband pattern optimization algorithms are needed. In some instances, the wideband pattern optimization algorithms will make it possible to meet performance objectives with phase only control along with fixed, but atypical, power division architecture.

PHASE I: Develop detailed conceptual designs for high-efficiency two-octave (UHF through L-band) array beamformers. The preferred solution set will be determined after developing optimization algorithms for fixed-amplitude variable-phase solutions and variable-amplitude variable-phase solutions. A set of embedded element patterns and desired array radiation pattern sets will be provided. Key in the selection is the resistive loss introduced into the beamformer by amplitude and phase control components. Reducing the sidelobe level at the expense of antenna gain is one of the beamformer tradeoffs in the selection process.

PHASE II: Utilizing phase I results design, assemble and demonstrate a prototype array beamformer capable of controlling a 36-element array in monopulse operation. Investigate and define the packaging and I/O requirements to ensure suitability for transition of the design into the E-2D Advanced Hawkeye aircraft.

PHASE III: Working with sensor system OEMs, fabricate an advanced array beamformer satisfying E-2D sensor system requirements. Transition the beamforming system to the operational fleet.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: High performance array beamformers are needed on a wide range of civilian and military sensor systems.

REFERENCES:
1. Van Trees, H.L., Optimum Array Processing, Part IV of Detection, Estimation, and Modulation Theory, John Wiley & Sons, New York, 2002
2. Wirth, W.-D., Radar Techniques Using Array Antennas (Radar, Sonar, Navigation and Avionics Series; No. 10), The Institution of Electrical Engineers, London, 2001
3. Fourikis, N., Advanced Array Systems, Applications and RF Technologies, Academic Press, London, 2000

KEYWORDS: Array Processing; Beamforming; Antenna Array Systems; Array Amplitude Control; Array Phase Control; Broadband Array; Array Pattern Synthesis

TPOC: (301)342-2637
2nd TPOC: (301)757-9553

** TOPIC AUTHOR (TPOC) **

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