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An active phased array or active electronically scanned array (AESA) is a phased array in which each antenna element has an analog transmitter/receiver (T/R) module [13] which creates the phase shifting required to electronically steer the antenna beam. Active arrays are a more advanced, second-generation phased-array technology that are used ...
An optical phased array (OPA) is the optical analog of a radio-wave phased array. [1] By dynamically controlling the optical properties of a surface on a microscopic scale, it is possible to steer the direction of light beams (in an OPA transmitter [ 2 ] ), or the view direction of sensors (in an OPA receiver [ 3 ] ), without any moving parts.
The first module, a linear array, was completed in 1960. It formed the basis of the AN/FPS-85. [1] Starting in the 1960s, new solid-state devices capable of delaying the transmitter signal in a controlled way were introduced. That led to the first practical large-scale passive electronically scanned array, or simply phased array radar.
Weld examination by phased array. TOP: The phased array probe emits a series of beams to flood the weld with sound. BOTTOM: The flaw in the weld appears as a red indication on the instrument screen. Phased array ultrasonics (PA) is an advanced method of ultrasonic testing that has applications in medical imaging and industrial nondestructive ...
In a radio antennas, the main lobe or main beam is the region of the radiation pattern containing the highest power or exhibiting the greatest field strength.. The radiation pattern of most antennas shows a pattern of "lobes" at various directions, where the radiated signal strength reaches a local maximum, separated by "nulls", at which the radiation falls to zero.
An antenna may have more than one driven element, although the most common multielement antenna, the Yagi, usually has only one. For example, transmitting antennas for AM radio stations often consist of several mast radiators, each of which functions as a half-wave monopole driven element, to create a particular radiation pattern.
A phased array usually means an electronically scanned array; a driven array antenna in which each individual element is connected to the transmitter or receiver through a phase shifter controlled by a computer. The beam of radio waves can be steered electronically to point instantly in any direction over a wide angle, without moving the antennas.
In a virtually imaged phased array, the phased array is the optical analogue of a phased array antenna at radio frequencies. Unlike a diffraction grating which can be interpreted as a real phased array, in a virtually imaged phased array the phased array is created in a virtual image. More specifically, the optical phased array is virtually ...