Faceted Array Antennas for Adaptive Beamforming Applications

In this paper, the performance of adaptive array antennas conformed to different faceted structures, namely, 2-faceted, 3-faceted, 4-faceted and 8-faceted structures, are studied and compared with each other in the context of adaptive beamforming. Faceted array antennas are chosen because they can achieve a wider scanning range compared to planar arrays. Each of the faceted arrays consists of eight circularly polarised antennas operating at 2.4 GHz. Beamforming is achieved according to two different optimisation criteria, which are the minimised mean square error (MMSE) and the maximised signal-to-interference-plus-noise ratio (MSINR). The adaptive algorithm, Least Mean Square (LMS), and the bio-inspired algorithm, Particle Swarm Optimisation (PSO), are used to calculate the complex excitations of the array elements in order to satisfy the optimisation criteria. The directivity of the 3-faceted array is high, 12.59 dBi, even when the desired signal is away from boresight. The results obtained suggest that the 3-faceted array is the most suitable for adaptive array applications compared to the other faceted structures.