Optical BEAMTAP beam-forming and jammer-nulling system for broadband phased-array antennas

Area of Science:

• Electrical Engineering
• Signal Processing
• Optics

Background:

• Adaptive antenna arrays are crucial for modern radar, sonar, and communication systems.
• Conventional beamforming techniques require substantial hardware, especially for large, broadband arrays.
• Existing methods struggle with complex spatiotemporal signal environments.

Purpose of the Study:

• To present an efficient and compact optical implementation for broadband beamforming and jammer nulling.
• To introduce a novel algorithm that drastically reduces hardware requirements for adaptive antenna arrays.
• To enable optimal adaptation to complex signal environments using photonic systems.

Main Methods:

• Development of the broadband efficient adaptive method for true-time-delay array processing (BEAMTAP) algorithm.
• Utilizing radio frequency (RF) photonic systems with coherent optically modulated fiber-optic feed networks.
• Employing gratings in photorefractive crystals for adaptive weights and acousto-optic devices for weight adaptation control.

Main Results:

• Reduced the number of tapped delay lines from N to 2 for an N-element phased-array antenna.
• Achieved full NM degrees of freedom with significantly reduced hardware compared to conventional methods.
• Demonstrated the capability to adapt to broadband signals, interference, and jammers from arbitrary angles.

Conclusions:

• The BEAMTAP algorithm offers enormous savings in delay-line hardware for large broadband arrays.
• Photonic systems, leveraging photorefractive crystals, can control arbitrarily large antenna arrays.
• This approach surpasses conventional RF and digital signal processing techniques for complex adaptive array applications.