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ECE Objective Questions { Antenna }



64. An antenna is a device
A. that converts electromagnetic energy into an RF signal
B. that converts RF signal into electromagnetic energy
C. that converts guided electomagnetic waves into free space electromagnetic waves and vice versa
D. none of these

65. The directive gain of antenna is defined as the
A. ratio of the average radiated power to the radiated power in a given direction
B. ratio of the radiation intensity in a given direction to that of the radiation intensity in the same direction due to a hypothetical isotropic radiator that radiates the same total power
C. ratio of the radiation intensity in a given direction due to a hypothetical isotropic radiator to the radiation intensity in the the samedirection due to the actual antenna
D. none of these

66. Directivity of an antenna is
A. same as its directive gain
B. directive gain expressed in decibels
C. the maximum value of its directive gain
D. none of these

67. An antenna having a higher 'Q' has
A. a higher bandwidth structure of horizontally polarised electromagnetic waves
B.vertically polarised electromagnetic waves
C.circularly polarised electromagnetic waves
D. none of these

68. Refer to the antenna Fig. 13.1. It is
A. a log-periodic antenna
B. a driven array
C. a broadside parasitic array
D. Yagi-antenna

69. an antenna placed in the horizontal plane produces
A. horizontally polarised electromagnetic waves
B.verticallypolarised electromagnetic waves
C. elliptically polarised electromagnetic waves
D. none of these

70. A Yagi antenna in the horizontal plane produces
A. an end fire directional pattern
B. a broadside directional pattern
C. a figure eight directional pattern
D. none of these

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