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ECE Objective Questions { Antenna }

78. AV-antenna consists of
A. two wires with an apex angle of 45?
B. two (X/2) long wires with an apex angle of 45?
C. two (V4) long wires with an apex angle of 45?
D. none of these

79. One of the following is an non-resonant antenni
A. The folded dipole
B. The endfire array
C. The broadside array
D. The rhombic antenna

80. One of the following antenna types is best excited from a waveguide
A. Horn antenna
B. Helical antenna
C. Biconical antenna
D. Log-periodic antenna

81. Top loading is used with antennas to
A. increase the effective height
B. reduce the effective height
C. increase the bandwidth
D. increase the input capacitance

82. A helical antenna is used for satellite tracking because of its
A. large bandwidth
B. large gain
C. circular polarization
D. maneuverability

83. The antenna of Fig. 13.2(a) produces
A. horizontal polarised waves
B. circularly polarised waves
C. vertically polarised waves
D. none of these

84. Fig. 13.3 shows the power densit radiation pattern of a certain antenna. The beamwidth of the antenna is
A.an upper bandwidth
B. a lower bandwidth
C. a flat response
D. none of these

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