Beamforming is a technique by which an array of antennas can be steered to transmit radio signals in a specific direction. Rather than simply broadcasting energy/signals in all directions, the antenna arrays that use beamforming, determine the direction of interest and send/receive a stronger beam of signals in that specific direction. 

This technique is widely used in radars and sonar, biomedical, and particularly in communications (telecom, Wi-Fi), specially 5G – Where very high data rates are required and the only way to support this would be to maximize transmit and receive efficiency by using beamforming.

In this technique, each antenna element is fed separately with the signal to be transmitted. The phase and amplitude of each signal is then added constructively and destructively in such a way that they concentrate the energy into a narrow beam or lobe.