Multi-beam Luneburg lens antenna for cellular communications

In this paper, we propose a Luneburg lens based multi-beam antenna solution for cellular communications. The solution uses a Luneburg lens fed by an array of appropriately placed dual-polarized radiators. As the coupling between the dual-polarized radiators and the reflections from the Luneburg lens are small, a beam-to-beam isolation of better than 30dB is achieved. Contemporary air interfaces such as LTE significantly benefit from high isolation between beams/sectors yielding much higher capacity/throughput. Furthermore, because of the spherical symmetry of the lens, the beams are identical and symmetrical in shape. Our Luneburg lens multi-beam antenna is broadband and provides up to 120° angular coverage with minimal beam variation in frequency due to the special design of the radiators. The cross-over between adjacent beams is designed for a nominal value of -10dB, which is generally accepted as optimal for 3G and 4G wireless network operation. It has been tested and shown to significantly improve the capacity of base station.