2019 IEEE International Symposium on Phased Array Systems and Technology

October 18, 2019 8 a.m. – 12 noon

Instructor:

Dr. Alfonso Farina, Selex, ret.
Consultant to Leonardo S.p.A. “Electronics Division”, Rome, Italy.

Abstract: Beamforming permits steering an antenna array in a way to obtain a certain antenna gain in a given direction while having suitable attenuation in others. Such spatial filtering, which combines the energy over the antenna aperture, is widely used in a variety of e.m. applications including phased arrays radars. In fact, the capability to maximize the signal of interest while minimizing possible interferences that could be present in operational environments is decisive for present and future active array antenna radars.

With the advent of digitally scanned array antennas, radar systems are equipped with hundreds of receiving channels each with a dedicated high speed Analogue to Digital Converter (ADC). Signal samples are captured in the proximity of the antenna and the digital signal processing is carried out afterwards to find the optimum weights for every receiving channel, thus accomplishing adaptive digital beamforming. Therefore, today array antennas can adjust their characteristics in response to environmental changes such as direction of arrival (DOA), frequency, interference rejection, polarization and power level. This self-adjusting capability makes array antenna operations more reliable and guarantees improved reception and resilience against possible interference signals that may be present in the environment.

The tutorial is organized into four parts. The first introduces the fundamental principles of beamforming and traces its history from analog to fully digital. The second describes the mathematical tools to carry out beamforming, for example focusing on linear/planar/circular/cylindrical/conformal arrays, performance
parameters, pattern types, transmission and reception adaptivity, SAR (Synthetic Aperture Radar), RF (Radio Frequency) tomography. The third presents significant case studies from open literature, illustrating the practical application of adaptive beamforming techniques to real-world systems. The fourth highlights some promising and evolving technologies (e.g., quantum radars and cognitive radars) that are paving the way to the future for adaptive digital beamforming. Comprehensive reference list will be provided.