The 3 dB beam width of a sparse array is inversely proportional to the aperture size A, which means that using them to make cooling easier will mean accepting the design tradeoff of a narrower beam. Using reasonable assumptions for an access point with a range of 150 m, simple calculations show that the maximum achievable beam width is probably 5 to 8 degrees – effectively a pencil beam.
Many research challenges remain before 5G systems will be deployed in the field. The most important ones for the physical hardware are reduction of power consumption and development of low-cost assembly techniques for the array panels.
 Maria Carolina Vigano, Sunflower array antenna for multi-beam satellite applications, PhD Thesis TU Delft, 2011, ISBN 987-94-6113-030-3
About the Author
Rik Jos holds a PhD in Physics from the University of Utrecht, The Netherlands. In 1986 he joined Philips Semiconductors in the development of RF technologies for power amplifier applications, where he was appointed a Philips Semiconductor Technology Fellow in 2002. Since 2004 he is also an adjunct professor at Chalmers University in Sweden. He has held leading positions in RF innovation in Philips and NXP Semiconductors. Since 2015 he is part of Ampleon in The Netherlands where he works on innovation of RF power technologies, especially wide bandgap semiconductors, and amplifier architectures, like switch mode power amplifiers. His current research activities focus on 5G mm-wave technologies and architectures.