Antennas And Microwave Engineering Set 2 MCQs

Q1 | If the beam width of an antenna in two orthogonal planes are 300 and 600. Then the directivity of the antenna is:

24

18

36

12

Q2 | If the power input to an antenna is 100 mW and if the radiated power is measured to be 90 mW, then the efficiency of the antenna is:

75 %

80 %

90 %

insufficient data

Q3 | If an antenna has a directivity of 16 and radiation efficiency of 0.9, then the gain of the antenna is:

16.2

14.8

12.5

19.3

Q4 | Gain of an antenna is always greater than the directivity of the antenna.

true

false

Q5 | A rectangular horn antenna has an aperture area of 3λ × 2λ. Then the maximum directivity that can be achieved by this rectangular horn antenna is:

24 db

4 db

19 db

insufficient data

Q6 | A rectangular horn antenna has an aperture area of 3λ × 2λ. If the aperture efficiency of an antenna is 90%, then the directivity of the antenna is:

19 db

17.1 db

13 db

21.1 db

Q7 | A resistor is operated at a temperature of 300 K, with a system bandwidth of 1 MHz then the noise power produced by the resistor is:

3.13×10-23 watts

4.14×10-15 watts

6.14×10-15 watts

none of the mentioned

Q8 | With an increase in operating frequency, the background noise temperature:

increases

decreases

remains constant

remains unaffected

Q9 | The noise temperature of an antenna is given by the expression:

radtb + (1-rad) tp

(1-rad) tp

radtb

none of the mentioned

Q10 | Low is the G/T ratio of an antenna, higher is its efficiency.

true

false

Q11 | has a constant power spectral density.

white noise

gaussian noise

thermal noise

shot noise

Q12 | Slotted line is a transmission line configuration that allows the sampling of:

electric field amplitude of a standing wave on a terminated line

magnetic field amplitude of a standing wave on a terminated line

voltage used for excitation

current that is generated by the source

Q13 | A modern device that replaces a slotted line is:

digital cro

generators

network analyzers

computers

Q14 | If the standing wave ratio for a transmission line is 1.4, then the reflection coefficient for the line is:

0.16667

1.6667

0.01667

0.96

Q15 | If the reflection coefficient of a transmission line is 0.4, then the standing wave ratio is:

1.3333

2.3333

0.4

0.6

Q16 | In the expression for phase of the reflection coefficient, Lmin stands for :

distance between load and first voltage minimum

distance between load and first voltage maximum

distance between consecutive minimas

distance between a minima and immediate maxima

Q17 | If the normalized load impedance of a transmission line is 2, then the reflection co- efficient is:

0.33334

1.33334

1

Q18 | Link budget consists of calculation of

useful signal power

interfering noise power

useful signal & interfering noise power

none of the mentioned

Q19 | Which is the primary cost for degradation of error performance?

loss in signal to noise ratio

signal distortion

signal distortion & loss in signal to noise ratio

none of the mentioned

Q20 | Which factor adds phase noise to the signal?

jitter

phase fluctuations

jitter & phase fluctuations

none of the mentioned

Q21 | Antennas are used

as transducer

to focus

as transducer & to focus

none of the mentioned

Q22 | Mechanism contributing to a reduction in efficiency is called as

amplitude tapering

blockage

edge diffraction

all of the mentioned

Q23 | Space loss occurs due to a decrease in

electric field strength

efficiency

phase

signal power

Q24 | Antenna’s efficiency is given by the ratio of

effective aperture to physical aperture

physical aperture to effective aperture

signal power to noise power

losses

Q25 | Effective radiated power of an isotropic radiator can be given as a product of

radiated power and received power

effective area and physical area

transmitted power and transmitting gain

receiving power and receiving gain