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WorksheetsAntenna & Wave Propagation-Module 1
Total questions: 25
Worksheet time: 35mins
Power density is basically termed as ..........power per unit area
Reflected
Refracted
Radiated
Diffracted
According to Webster's dictionary, what is an antenna?
Impedance matching device
Sensor of electromagnetic waves
Transducer between guided wave & free space wave
Metallic device for radiating or receiving radio waves
In a non-isotropic directional antenna, which radiating lobe axis makes an angle of 180° w.r.t. major beam of an antenna?
Minor lobe
Side lobe
Back lobe
None of the above
Which property/ies of antenna is/are likely to be evidenced in accordance to Reciprocity theorem?
Equality of impedances
Equality of directional patterns
Equality of effective lengths
All of the above
If an antenna draws 12 A current and radiates 4 kW, then what will be its radiation resistance?
22.22 ohm
27.77 ohm
33.33 ohm
39.77 ohm
Linear polarization can be obtained only if the wave consists of ________
Ex
Ey
Both Ex & Ey & in phase
Both Ex & Ey & out of phase
According to depth of penetration, what is the percentage proportion of attenuated wave w.r.t its original value?
17
27
37
57
In retarded potentials, what factor of time delay is generally introduced in A & V equations?
R + c
R - c
R/c
R x c
The vector magnetic potential shows the inverse relationship with its ____
Source
Distance of point from the source (R)
Both a and b
None of the above
According to the geometry, how many sterdians are present in a full sphere?
π/2
π
2π
4π
If a half-wave dipole operates at 300 MHz with λ = 0.5m & D0 = 1.643, what will be its effective area?
0.032 m2
0.047 m2
0.65 m2
0.99 m2
Sterdian is a measurement unit of __________
Point angle
Linear angle
Plane angle
Solid angle
Which among the following defines the angular distance between two points on each side of major lobe especially when the radiation drops to zero?
Half power beam width (HPBW)
First null beam width (FNBW)
Side lobe level (SLL)
Front to back ratio (FBR)
What is the nature of radiation pattern of an isotropic antenna
Spherical
Dough-nut
Elliptical
Hyperbolic
If HPBW in both planes are 20°, then find directivity in dBi using approximation.
20
40
60
100
An antenna has a field pattern given by E(θ)=cos²(θ) for 0≤θ≤90°. Find the beam area of this pattern.
0.57 sr
3.57 sr
1.26 sr
2.56 sr
The radiation resistance of an antenna is 72 Ω, and loss resistance is 8Ω. Find D if power gain=16
17
17.52
17.78
17.9
For a sphere of radius r, find the solid angle Ωₐ( in square radians) of a spherical cap on the surface of the sphere over the north pole region defined by spherical angles 0≤θ≤30°, 0≤Φ≤360°.
0.56
0.67
0.78
.84
Effective Aperture of an antenna is defined as
Ratio of power received to the Poynting Vector of Incident wave.
Ratio of Poynting Vector of Incident wave to the power received.
Ratio of power received to the Poynting Vector of reflected wave.
Ratio of Poynting Vector of reflected wave to the power received.
Maximum directive gain of a short dipole is...........
1.3
1.4
1.5
1.6
Calculate the effective length of a half wave dipole antenna. Given Radiation resistance =73Ω, Maximum effective aperture =0.13λ² and η=120π.
0.2394λ
0.3174λ
0.3523λ
0.4352λ
Calculate the maximum effective aperture of an antenna which is operating at a wavelength of 2m and has a directivity of 100.
29.56
30.98
31.84
32.45
The value of radiation resistance depends on
Configuration of antenna
Point where radiation resistance is considered
Location of antenna wrt grounds
Antenna Bandwidth
Corona discharge
The expression for Antenna Temperature, T is
(a)
The field at a large distance from the antenna is called
Fraunhofer region
Fresnel region
