Deck 2: Antenna and Transmission Line

Question 1

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

A)24 db
B)4 db
C)19 db
D)insufficient data

Answer 1

19 db

Question 2

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

A)19 db
B)17.1 db
C)13 db
D)21.1 db

Answer 2

17.1 db

Question 3

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

A)increases
B)decreases
C)remains constant
D)remains unaffected

Answer 3

increases

Question 4

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

A)radtb + (1-rad) tp
B)(1-rad) tp
C)radtb
D)none of the mentioned

Question 5

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

Question 6

__________has a constant power spectral density.

A)white noise
B)gaussian noise
C)thermal noise
D)shot noise

Question 7

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

A)electric field amplitude of a standing wave on a terminated line
B)magnetic field amplitude of a standing wave on a terminated line
C)voltage used for excitation
D)current that is generated by the source

Question 8

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

A)0.16667
B)1.6667
C)0.01667
D)0.96

Question 9

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

A)1.3333
B)2.3333
C)0.4
D)0.6

Question 10

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

A)distance between load and first voltage minimum
B)distance between load and first voltage maximum
C)distance between consecutive minimas
D)distance between a minima and immediate maxima

Question 11

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

A)0.33334
B)1.33334
C)0
D)1

Question 12

Link budget consists of calculation of

A)useful signal power
B)interfering noise power
C)useful signal & interfering noise power
D)none of the mentioned

Question 13

Which is the primary cost for degradation of error performance?

A)loss in signal to noise ratio
B)signal distortion
C)signal distortion & loss in signal to noise ratio
D)none of the mentioned

Question 14

Which factor adds phase noise to the signal?

A)jitter
B)phase fluctuations
C)jitter & phase fluctuations
D)none of the mentioned

Question 15

Antennas are used

A)as transducer
B)to focus
C)as transducer & to focus
D)none of the mentioned

Question 16

Mechanism contributing to a reduction in efficiency is called as

A)amplitude tapering
B)blockage
C)edge diffraction
D)all of the mentioned

Question 17

Space loss occurs due to a decrease in

A)electric field strength
B)efficiency
C)phase
D)signal power

Question 18

Antenna's efficiency is given by the ratio of

A)effective aperture to physical aperture
B)physical aperture to effective aperture
C)signal power to noise power
D)losses

Question 19

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

A)radiated power and received power
B)effective area and physical area
C)transmitted power and transmitting gain
D)receiving power and receiving gain

Question 20

A dipole antenna is also called as?

A)marconi antenna
B)yagi antenna
C)bidirectional antenna
D)hertz antenna

Question 21

The impedance at the center of the antenna is known as?

A)characteristic impedance
B)radiation resistance
C)transmission impedance
D)recovery resistance

Question 22

What happens when the radiation resistance of the antenna matches the characteristic impedance of the transmission line?

A)no transmission occurs
B)no reception occurs
C)swr is maximum
D)swr is minimum

Question 23

The type of dipole antenna that has a higher band width is called as?

A)conical antenna
B)yagi antenna
C)helical antenna
D)marconi antenna

Question 24

The radiation pattern of a half-wave dipole has the shape of a __________

A)doughnut
B)sphere
C)hemisphere
D)circular