This set of Antenna Multiple Choice Questions & Answers (MCQs) focuses on “Feeding Systems”.
1. In which of the following cases, a parabolic reflector primary radiator is said to be ideal feed?
a) The entire reflector is illuminated with no radiation in unwanted direction when feed radiated entire energy towards it
b) Some part of reflector is illuminated with no radiation in unwanted direction when feed radiated entire energy towards it
c) Some part of reflector is illuminated with radiation in unwanted direction when feed radiated entire energy towards it
d) The entire reflector is illuminated with small radiation in unwanted direction when feed radiated entire energy towards it
2. To obtain maximum beam pattern, the primary radiator is placed ______ in a reflector antenna.
a) between Focus and Directrix
b) after the focus
c) at the focus point
d) can be placed anywhere
3. Which of the following is called as the source placed at the focus?
a) Feed radiator
c) Secondary radiator
d) Primary / reflector
4. When the feed is moved along the main axis in a reflector antenna what happens to the beam pattern?
a) It broadens
b) It deteriorates
c) Beam remains unchanged
d) Side lobes are increased
5. In a Cassegrain feed system; the feed is placed at _____
d) Anywhere between vertex and focus
6. Which of the following regarding the Cassegrain feed system is false?
a) Spill over is reduced
b) It is a dual reflector antenna
c) Minor lobe radiation increases
d) A convex sub-reflector is used
7. The beam gets deteriorated when it is moved along a line perpendicular to the main axis passing through focus?
8. Which of the following coincides with the focus of the parabolic reflector in a Cassegrain antenna?
b) Parabolic reflector
c) Focus of hyperboloid reflector
d) Focus of primary radiator
9. When a dipole with a parasitic reflector is used as a feed system, the distance between them is _____
10. Which of the following uses a concave sub-reflector in a dual reflector antenna?
c) Both Gregorian &Cassegrain
d) Neither Gregorian nor Cassegrain