Advantages of Phased Array Antenna | disadvantages of Phased Array Antenna
This page covers advantages and disadvantages of Phased Array Antenna. It mentions Phased Array Antenna advantages or benefits and Phased Array Antenna disadvantages or drawbacks. It also describes phased array antenna basics.
What is Phased Array Antenna?
As we know conventional antennas such as parabolic reflectors are difficult to move either in azimuth or in elevation as they are bulky. Moreover it requires more time as it is controlled by servo motors and actuators. The phased array antenna utilizes electronic means to rotate the beam in desired direction.
To move or rotate the beam in desired direction, phase of transmitting elements in the array are varied by
a device known as phase shifter. The figure-1 depicts linear array of six antenna elements.
Dipoles, slots or horns are used as antenna elements.
The angle of beam from axis of the antenna depends on following parameters.
• Operating wavelength of signal
• Spacing between elements
• Phase shift between signals in the elements
The number of antenna elements in the phased array antenna is determined by the directivity specification.
The figure-2 depicts use of vertical dipoles in a phased array antenna. The radiation pattern of it is also mentioned alongside. Similarly horizontal dipoles can also be used in the phased array design. Refer Antenna tutorial >>, Antenna terminology >> and antenna types >>.
Following are the two possible arrangements employed in the phased array antenna.
• Linear array: The elements arranged in a line are fed from common phase shifter.
• Planar array:The elements arranged have their own phase shifters. They are arranged in matrix form.
Benefits or advantages of Phased Array Antenna
Following are the benefits or advantages of Phased Array Antenna:
➨It offers higher directivity. The higher the number of elements in an array, higher is the directivity.
➨It provides electronic steering and hence cumbersome mechanical steering using servo motors can be avoided. Hence beam can be moved in the desired direction in less than milliseconds.
➨It can be used for surveillance and tracking in radar.
➨It can emit multiple beams simultaneously to deliver multifunction operations.
➨Beam steering is possible in two planes using planar array configuration. Digital beamforming is also possible.
➨Linear array configuration requires very simple arrangement of elements.
Drawbacks or disadvantages of Phased Array Antenna
Following are the disadvantages of Phased Array Antenna:
➨The coverage is limited to 120 degrees in both azimuth and elevation.
➨Lower frequency agility can be achieved.
➨Ray deflection is possible only in single plane using linear array configuration.
➨Planar array configuration is very complex and requires phase shifter with advanced electronic controls.
➨It is available at higher costs.
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