This set of RF & Microwave Circuit Design Multiple Choice Questions & Answers (MCQs) focuses on “Antenna Radiation”.

1. Antennas that radiate energy only in a specified are called anisotropic antennas.

a) True

b) False

2. The expression for pointing vector of an isotropic point source at a distance ‘r’ from the source is given by:

a) P/ 4πR^{2}

b) P/4π

c) P/ 4πR

d) P×4πR^{2}

3. An antenna source that radiates energy uniformly in all the directions is called:

a) Isotropic source

b) Anisotropic source

c) Point source

d) None of the mentioned

4. A source has a cosine radiation-intensity pattern given by U=U_{M} cos (θ). The directivity of this source is:

a) 2

b) 4

c) 6

d) 8

5. A source has a radiation intensity pattern given by U=U_{M} sin θ. The directivity of the source with this power pattern is:

a) 1

b) 1.27

c) 2.4

d) 3.4

6. A source with a unidirectional cosine squared radiation intensity pattern is given by U_{M}cos^{2} (θ). The directivity of the given source is:

a) 6

b) 8

c) 2

d) 7

7. A source has a cosine power pattern that is bidirectional. Given that the directivity of a unidirectional source with cosine power pattern has a directivity of 4, then the directivity of the unidirectional source is:

a) 1

b) 2

c) 4

d) 8

8. A source has a sine squared radiation intensity power pattern. The directivity of the given source is:

a) 1.5

b) 3

c) 2.5

d) 3.5

9. Considering distance as a parameter, two types of field zones can be defined around an antenna.

a) True

b) False

10. If the field strength at receiving antenna is 1 µV/m, and the effective aperture area is 0.4 m^{2} and the intrinsic impedance of the medium is 377 Ω, then the power received by the antenna is:

a) 1.06 pW

b) 1.06 fW

c) 2 µW

d) None of the mentioned