Antennas And Microwave Engineering Set 2

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This set of Antennas and Microwave Engineering Multiple Choice Questions & Answers (MCQs) focuses on Antennas And Microwave Engineering Set 2

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