Beam Broadening for Phased Antenna Arrays Using Multi-Beam Subarrays
Consideration of mmWave frequencies with large phased antenna arrays has become increasingly important for providing multi-Gb/s wireless data communication. However, large phased antenna arrays tradeoff gain for very narrow beam widths, which may not always be desirable for outdoor, mobile communication. This paper provides a systematic approach for beam broadening for phased antenna arrays, with unit amplitude constraint and without turning off antennas, using multi-beam sub-arrays and without any increase in hardware complexity. The authors first show that the beam resulting from the full array lies in the region defined by the sum of the individual sub-arrays and beams can be shaped within the region using RF or baseband phase pre-coding.