Friday, 22 April 2016

Antenna Arrays

Antenna Arrays :

Antennas with a given radiation pattern may be arranged in a pattern line, circle, plane, etc.) to yield a different radiation  pattern.

Antenna array - a configuration of multiple antennas (elements) arranged to achieve a given radiation pattern.

Simple antennas can be combined to achieve desired directional effects.Individual antennas are called elements and the combination is an array

Types of Arrays

1. Linear array - antenna elements arranged along a straight  line.

2. Circular array - antenna elements arranged around a circular ring.

3. Planar array - antenna elements arranged over some planar surface (example - rectangular array).

4. Conformal array - antenna elements arranged to conform two some non-planar surface (such as an aircraft skin).

Design Principles of Arrays

There are several array design variables which can be changed to achieve the overall array pattern design.

Array Design Variables

1. General array shape (linear, circular,planar)

2. Element spacing.

3. Element excitation amplitude.

4. Element excitation phase.

5. Patterns of array elements.

Types of Arrays

• Broadside: maximum radiation at right angles to main axis of antenna

• End-fire: maximum radiation along the main axis of  antenna

• Phased: all elements connected to source

• Parasitic: some elements not connected to source

• They re-radiate power from other elements

Article by
St.Mary's Group
ECE Dept.

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