What is Beamforming?

A technique that adjusts the phase (and amplitude) of each of several antenna elements so that radio waves reinforce one another in a particular direction for transmission or reception. Changing the phases electronically steers the beam without moving the antenna (a phased array). Besides making up for the large propagation loss of millimeter-wave bands, it is used in 5G base stations and wireless LANs to point a beam at each terminal, raising received power and reducing interference.

Japanese name: ビームフォーミング

Beamforming appears in 3 practice questions across 1 topic, including Wireless Communication Basics.

Field: Wireless Communication Basics

Try it: questions about Beamforming

Which is the most appropriate main reason that beamforming with array antennas of many elements is used in 5G millimeter-wave base stations and terminals?

ABecause the wavelength is short, many elements fit in a small area, and the high gain of a sharp beam makes up for the large propagation loss
BBecause multipath never occurs in millimeter-wave bands, the beam direction never needs to change once set
CBecause increasing the number of antenna elements reduces the propagation loss along the path itself

Show answer and explanation

Answer: A. Because the wavelength is short, many elements fit in a small area, and the high gain of a sharp beam makes up for the large propagation loss

Antenna elements are generally spaced about half a wavelength apart, so in millimeter-wave bands with wavelengths of around 1 cm, several tens of elements fit within a few centimeters square. The more elements, the sharper the beam and the higher the gain in its direction, which makes up for the large propagation loss of millimeter-wave bands. Because the beam is narrow, however, its direction must be searched for again and tracked as the terminal moves or the human body blocks it. Even in bands below 6 GHz, massive MIMO with many elements at the base station is used to communicate with many terminals at once through spatial multiplexing.

Beamforming in the explanations

As a result, the area covered by one base station (a cell) becomes small, and beamforming with many antenna elements concentrates the waves toward the terminal to make up for the loss.
Which is a general characteristic of radio waves in millime…
In beamforming, the antenna elements in an array transmit with shifted phases so that the waves reinforce in the desired direction and cancel in others.
Which technique adjusts the phase (and amplitude) of the si…

Questions that mention Beamforming (3)

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