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ECE Objective Questions { Antenna }

85. A non-resonant antenna is characterized bY
A. antenna being terminated in a resistance
B. the presence of only the forward travelling wave and absence of standing waves
C. a unidirectional radiation pattern
D. (a), (b) and (c)

86. A resonant antenna is characterised by
A. the presence of standing waves
B. a unidirectional, highly directional radiation pattern
C. a bidirectional radiation pattern
D. (a) and (c)

87. One of the following antennas can be used for direction finding
A. Half wave dipole
B. Loop antenna
C. Broadside antenna array
D. End fire antenna array

88. Microwave antennas have
A. high gain
B. high front to back ratio
C. high input impedance
D. low input impedance

89. An antenna that radiates 5 kW in its optimum direction and 50 watts in the opposite direction has a front to back ratio of
A. 20 dB
B. 40 dB
C. 10 dB
D. none of these

90. A resonant antenna is a system with
A. zero SWR
B. a very high SWR
C. a very low SWR
D. none of these

91. Most of the man made noise has
A. circular polarization
B. horizontal polarization
C. vertical polarization
D. elliptic polarisation

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