A phased array antenna is composed of lots of radiating elements each with a phase shifter. Beams are formed by shifting the phase of the signal emitted from each radiating element, to provide constructive/destructive interference so as to steer the beams in the desired direction.
In practical use, a phased array usually means an electronically scanned array, a computer-controlled array of antennas which creates a beam of radio waves that can be electronically steered to point in different directions without moving the antennas.
Phased array technology was pioneered for military applications. The ever increasing speed of aircraft and ordnance after the second world war pushed the requirement for antenna sweep time from seconds to milliseconds.
But now, phased-array antennas have become much sought after in a variety of applications. Modern electronically scanned arrays (AESAs) are now appearing in automotive driver assist systems, satellite communications and advanced radar.
Phased-array and 5G
Phased-array antennas have even become an important part of the new 5G broadband network.
5G is expected to offer extremely fast rates with extremely low latency. To achieve these tough specifications, the operating frequency must be in a region where high bandwidth and high speed is available. That means a move toward the millimeter-wave (mmWave) band.
The mmWave band had always been viewed as unsuitable for mobile communications, mainly due to high loss and propagation issues. However, research has shown that these propagation issues can be addressed and overcome with phased arrays and beam steering antennas.
Phased-array antennas allow engineers to enter the mmWave spectrum and achieve the high bandwidth and high speeds that 5G promises. Within the mmWave spectrum, the 28-GHz band has been chosen as one of the candidate bands to quantify 5G.
By controlling phase and amplitude of the input signal to the individual elements, one can achieve steerable directivity of the antenna beam over both azimuth and elevation.
Want to learn more about phased-array radar systems? Tonex offers Phased-Array Radar Systems Engineering Bootcamp, a 3-day course covering phased array radar principles, latest technological developments, software, system analysis, requirements, architecture, design and operation.
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