What are analog, digital and hybrid beamforming?
Beamforming applies complex weights (amplitude and phase, or time delay) to signals at each array element so they combine into one or more beams. Analog beamforming applies weights at RF or IF with phase shifters, forming one beam per RF chain; digital beamforming digitizes each element and forms any number of beams in software; hybrid beamforming combines analog subarrays with fewer digital chains, the common architecture for 5G mmWave.[1][2][3]
How do the architectures compare?
| Architecture | Beams | Cost/power | Typical use |
|---|---|---|---|
| Analog | One per RF chain | Lowest | mmWave terminals, satcom user terminals |
| Hybrid | A few | Medium | 5G mmWave base stations and terminals |
| Digital | Many simultaneous, adaptive | Highest | Sub-6 GHz massive MIMO, modern radar |
What are fixed beam networks?
Passive beamforming networks such as the Butler matrix and Rotman lens produce a fixed set of orthogonal beams from N inputs; the Rotman lens uses true time delay and is therefore squint-free over wide bandwidths.[4][2]
What is adaptive beamforming?
Weights are computed from the received data to maximize signal-to-interference-plus-noise ratio, steering nulls toward interferers. In communications, precoding based on channel state information (e.g., zero-forcing, MMSE) generalizes beamforming to multiple users.[1][5]
Frequently asked questions
Is beamforming the same as MIMO?
Beamforming is one MIMO technique; MIMO also includes spatial multiplexing and diversity.
Does Wi-Fi use beamforming?
Yes; IEEE 802.11ac/ax define explicit transmit beamforming using channel sounding.
Why not fully digital at mmWave?
Power consumption and cost of many wideband converters.
See also
References
Online sources accessed October 21, 2026; printed works cited by edition. See all sources.
- “Foundations of MIMO Communication”. R. W. Heath Jr. and A. Lozano, Cambridge University Press. 2018.
- “Phased Array Antenna Handbook, 3rd ed.”. R. J. Mailloux, Artech House. 2017.
- “Millimeter Wave Mobile Communications for 5G Cellular: It Will Work!”. T. S. Rappaport et al., IEEE Access, vol. 1, pp. 335-349. 2013.
- “Phased Array Antennas, 2nd ed.”. R. C. Hansen, Wiley. 2009.
- “Massive MIMO for Next Generation Wireless Systems”. E. G. Larsson, O. Edfors, F. Tufvesson and T. L. Marzetta, IEEE Communications Magazine, vol. 52, no. 2, pp. 186-195. February 2014.