A Multiple Switched Beam Smart Antenna with Beam Shaping for Dynamic Optimisation of Capacity & Coverage in Mobile Telecommunication Networks

A four column Smart antenna array fed by a 4x4 Butler matrix augmented by a variable beam shaping network has been designed and simulated. It is demonstrated that using only three phase shifters within the beam shaping network provides dynamic beam flexibility including: four narrow switched beams, a right shaped beam, a left shaped beam and a broad broadcast channel beam. The shaped beams concentrate coverage at high capacity in either the right or left half of a sector while maintaining coverage at lower capacity over the reminder of the sector. The resultant antenna system represents an improvement in performance over a single multiple switched beam smart antenna without the cost and complexity of a fully adaptive smart antenna. Simulated radiation patterns over the full 3G frequency band show that useful dynamic coverage & capacity enhancement can be implemented with the proposed antenna system.