WorksheetsAntenna Class Test
Total questions: 10
Worksheet time: 6mins
Analyze the behavior of an antenna in the near-field region and identify which quantity dominates in this zone.
Reactive fields
radiated fields
impedance
Gain
Analyze the behavior of an antenna in the far-field region and identify which quantity dominates in this zone.
reactive field
radiated field
Identify the parameter that defines the ratio of maximum radiation intensity to average radiation intensity of an antenna
Radiation pattern
Directivity
impedance
Efficiency
Apply the relation between gain and directivity to determine the gain of an antenna with a directivity of 8 dBi and an efficiency of 0.75.
6.75dBi
9.25dBi
1.25dBi
3.25dBi
Analyze how beam area influences the directivity of an antenna system: An antenna has a beam solid angle of 1.5 steradians.
Compare this with another antenna having a beam solid angle of 0.8 steradians.
Which antenna has higher directivity, and why?
Both antennas have the same directivity, since beam area doesn’t affect it.
The antenna with 1.5 sr beam area, because directivity increases with beam area.
The antenna with 0.8 steradians beam area, because directivity is inversely proportional to beam area.
Directivity is independent of beam area and depends only on gain.
Identify the directivity value of an isotropic antenna?
0
1
2
3
Evaluate the maximum effective aperture of a microwave antenna with a directivity of 900.
71.6 m2
7 λ2 m2
6 λ2 m2
71.6 λ2 m2
Analyze the primary function of the director element in a Yagi-Uda antenna.
Reflects energy away from the source
Increases forward gain by focusing radiation
Matches the impedance of the feedline
Evaluate why a Yagi-Uda antenna is more effective than a dipole in point-to-point communication systems.
Requires no alignment with the signal direction
Has a simpler construction
Provides higher gain and better directivity
Covers a wider frequency range
Determine the spacing required between the reflector and the driven element in a Yagi-Uda antenna operating at 300 MHz.
15-25%
100%
