Beamforming
Beamforming is a way of combining the signals from several antenna elements so that radio energy is concentrated in a chosen direction instead of being spread evenly.
What is Beamforming?
When several radiating elements send the same signal with carefully controlled timing (phase), their waves add together in some directions and cancel in others. The result behaves like one larger antenna with a narrower, stronger beam. Adding more elements makes the main beam narrower and the unwanted side lobes weaker. Beamforming is central to 5G, where it helps overcome the high losses of millimetre-wave frequencies, but the basic idea is over a century old.
How it works
In digital beamforming, the phase and amplitude of each element's signal are set in the baseband processor, which allows several beams at once. Analogue beamforming applies phase shifts in the radio frequency stage and is cheaper and more power-efficient, which suits millimetre-wave antennas. Hybrid designs combine the two.