Antenna Arrays

An antenna array (or array antenna) is a set of multiple connected antennas which work together as a _________ antenna, to transmit or receive radio waves.

• 
  Directivity increases

• Directivity decreases

• Beam width decreases

• 
  Gain increases

Which of the following statement is true?

• As the number of elements increase in array it becomes less directive

• As the number of elements increase in array it becomes more directive

• Point to point communication is not possible with more number of array element.

• There is no uniform progressive phase shift in linear uniform array

An antenna array (or array antenna) is a set of multiple connected antennas which work together as a _________ antenna, to transmit or receive radio waves.

• Different

• Single

• Independent

• None

Electrical size of antenna is increased by which of the following?

• Antenna Array

• Decreasing the coverage area
  

• Increasing the coverage area

• Using a single antenna

For long distance communication, which of the property is mainly necessary for the antenna?

• High directivity

• Low directivity

• Low gain

• Broad beam width

A uniform linear array contains _____________

• N elements placed at equidistance and fed currents of equal magnitude and progressive phase shift

• N elements at non-equidistance and fed currents of equal magnitude and progressive phase shift

• N elements at equidistance and fed currents of unequal magnitude and progressive phase shift

• N elements at equidistance and fed currents of unequal magnitude and equal phase shift

What is the progressive phase shift of the end-fire array?

• 0

• 90

• 180

• 270

The radiating pattern of single element multiplied by the array factor simply gives the ___________.

• Pattern multiplication

• Normalized array factor

• Beamwidth of the array

• Field strength of the array

In Broadside array the maximum radiation is directed with respected to the array axis at an angle____

• 0

• 45

• 90

• 180

Which of the following statements is false regarding a broadside array?

• The maximum radiation is normal to the axis of the array

• Must have same amplitude excitation but different phase excitation among different elements

• The spacing between elements must not equal to the integral multiples of λ

• The phase excitation difference must be equal to zero