Advanced Antenna Array Beamformers

The goal of this project is to design multi-octave beamformer systems capable of compensating for on-aircraft effects on element patterns. This requires addressing (1) mutual coupling in the array, and (2) near-field scattering from the airborne platform. Amplitude and phase control at each element of the array could be employed to compensate for the on-aircraft effects but the power loss caused by amplitude control may be unacceptable. Also the desire for wide bandwidth operation will necessitate different corrections at the various frequencies. In particular the difference beam generated by the beamformer will be very sensitive to mutual coupling/near-field scattering effects and the variation of these effects as a function of bandwidth. The objective is to develop an optimization algorithm approach for high-efficiency two-octave (UHF through L-band) array beamformers. This approach will compensate for on-aircraft effects (mutual coupling, near-field scattering). The beamformer performance will be calculated for a system using (1) the embedded element patterns provided by the government, and (2) the UHF and L-band element patterns of a 36 log-periodic element array on an E2-C platform calculated using an electromagnetic code. In both cases performance will be evaluated using (1) amplitude and phase control and (2) phase-only control.