Question

Which of the following is false regarding a paraboloid antenna?

(a) Spill over decreases due to back lobe of primary radiator

(b) Feed placed at the focus is used to improve the beam pattern

(c) Pill box provides wide beam in one plane and narrow beam in other plane

(d) At lower frequencies parabolic antennas are not used frequently

Answer 1

The correct choice is (a) Spill over decreases due to back lobe of primary radiator

Easiest explanation: Spill over occurs due to the non-captured radiation by the reflector. From the primary radiators also some of forward radiation gets added up with the desired parallel beams. This is called back lobe radiation. It increases due to the back lobe of the primary radiator.