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The term "phased array" is also used to a lesser extent for non steerable array antennas in which the phase of the feed power and thus the radiation pattern of the antenna array is fixed. [ 8 ] [ 11 ] For example, AM broadcast radio antennas consisting of multiple mast radiators fed so as to create a specific radiation pattern are also called ...
The Eurofighter Typhoon combat aircraft with its nose fairing removed, revealing its Euroradar CAPTOR AESA radar antenna. An active electronically scanned array (AESA) is a type of phased array antenna, which is a computer-controlled antenna array in which the beam of radio waves can be electronically steered to point in different directions without moving the antenna. [1]
An antenna array (or array antenna) is a set of multiple connected antennas which work together as a single antenna, to transmit or receive radio waves. [ 1 ] : p.149 [ 2 ] The individual antennas (called elements ) are usually connected to a single receiver or transmitter by feedlines that feed the power to the elements in a specific phase ...
A typical radiation pattern of phased arrays whose inter-element spacing is greater than half a wavelength, hence the radiation pattern has grating lobes.. For discrete aperture antennas (such as phased arrays) in which the element spacing is greater than a half wavelength, a spatial aliasing effect allows plane waves incident to the array from visible angles other than the desired direction ...
In 1959, DARPA developed an experimental phased array radar called Electronically Steered Array Radar (ESAR). It was a large two-dimensional phased array with beam steering controlled by computers instead of requiring mechanical motion of the antenna. The first module, a linear array, was completed in 1960. It formed the basis of the AN/FPS-85. [1]
Most antennas boresight axis is fixed by their shape and cannot be changed. However phased array antennas can electronically steer the beam, changing the angle of the boresight by shifting the relative phase of the radio waves emitted by different antenna elements, and even radiate beams in multiple directions (multiple boresights). [1]
Phase-comparison monopulse is a technique used in radio frequency (RF) applications such as radar and direction finding to accurately estimate the direction of arrival of a signal from the phase difference of the signal measured on two (or more) separated antennas [1] or more typically from displaced phase centers of an array antenna.
Similarly, a lens-enhanced phased array antenna, similar to a transmitarray, has been demonstrated. [19] By combining the beam steering capabilities of phased arrays and the focusing properties of transmitarrays, this hybrid antenna has a smaller form factor, [20] and steers to ±45° in both planes with a 3.2 dB increase in directivity at