The phased array appropriately shifts the phase (or delay) of the array element signals arranged according to a certain law to obtain the deflection of the array beam, and at the same time compensates the phase (or delay) in different directions to obtain the multi-beam. Its advantage is that it is very convenient and flexible to realize the electric scanning of the light beam in the observed space without mechanically rotating the array. At the same time, the size of the array can be made larger to improve the spatial gain.
Phased array radar, that is, phased electronically scanned array radar, can scan the whole airspace within 1min because of its ability to change beams quickly and accurately. The so-called phased array radar is a radar array composed of a large number of identical radiating elements, and each radiating element is independently controlled by a wave control and a phase shifter in phase and amplitude, thus obtaining an accurate and predictable radiation pattern and beam pointing.
Advantages and characteristics of phased array
1, phased array adopts S-scan, that is, it can have ultrasonic waves with multiple angles at the same time, which is equivalent to the probe with multiple angles working at the same time, so phased array does not need sawtooth scanning, only needs to move the probe along the weld, and the detection efficiency is higher. Suitable for automatic production and mass production.
2. Phased array can have focusing function, but conventional ultrasound generally does not (except focusing probe), so the sensitivity and resolution of phased array detection are higher than that of conventional ultrasound detection.
3. Phased array detection can have B-scan, D-scan, S-scan and C-scan at the same time, and a three-dimensional graph can be established through modeling. Defect display is very intuitive, even people who don't know nondestructive testing can understand it, while conventional ultrasonic can only distinguish defects through waveforms.
The above contents refer to Baidu Encyclopedia-Phased Array.