1. What is the polarization loss factor when two antennas are rotated by an angle 30°?
a) 0.75
b) 0.25
c) 1
d) 0
Explanation: The polarization loss factor due to mismatch if the two linear polarized antennas are rotated by an angle ∅ is given by PLF = cos2∅
⇨ PLF = cos230=\(\frac{3}{4}=0.75\)
2. Which of the following is best described by the polarization loss factor?
a) Power loss due to mismatch
b) Height of antenna
c) Directivity
d) Power gain
Explanation: The polarization loss factor describes the power loss due to polarization mismatch. The polarization loss factor due to mismatch if the two linear polarized antennas are rotated by an angle ∅ is given by PLF =cos2∅.
3. The polarization of received antenna is not same as incident wave polarization is termed as ___
a) polarization mismatch
b) polarization loss factor
c) directivity
d) transmitter
Explanation: The polarization of received antenna is not same as incident wave polarization is termed as Polarization mismatch. The polarization loss factor describes the power loss due to polarization mismatch. PLF =cos2∅.
4. Which of the following is the condition for no power loss?
a) PLF=1
b) PLF=0
c) PLF=0.5
d) PLF=0.75
Explanation: Polarization loss factor describes the power loss. When PLF = 1 = 0dB indicates total power incident is received by the antenna. Therefore the condition for the no power loss is PLF=1
5. Which of the following limit is correct for the polarization loss factor?
a) 0≤PLF≤1
b) -1≤PLF≤1
c) -1≤PLF≤0
d) 0≤PLF≤∞
Explanation: The polarization loss factor due to mismatch if the two linear polarized antennas are rotated by an angle ∅ is given by PLF = cos2∅.
⇨ Max value of PLF = 1
⇨ Min value of PLF = 0
⇨ 0≤PLF≤1
6. Which of the following holds true for complete polarization mismatch?
a) PLF=1
b) PLF=0
c) PLF=0.5
d) PLF=0.75
Explanation: Polarization loss factor describes the power loss. When PLF=0=∞ dB, the receiver antenna doesn’t receive any incident power so there will be a complete mismatch.
7. Polarization loss factor describes the amount of power loss due to polarization mismatch at the receiving antenna from incident wave.
a) True
b) False
Explanation: Polarization loss factor describes the amount of power loss due to polarization mismatch at the receiving antenna from incident wave. The polarization loss factor due to mismatch if the two linear polarized antennas are rotated by an angle ∅ is given by PLF = cos2∅.
8. Polarization loss factor in dB when two linear polarized antennas are rotated by an angle 45° is ___
a) 3dB
b) -3dB
c) 0.5dB
d) -0.5dB
Explanation: The polarization loss factor due to mismatch if the two linear polarized antennas are rotated by an angle ∅ is given by PLF = cos2∅.
⇨ PLF = cos2∅=cos2 45=0.5=-3dB.
9. Which of the following statement is not correct?
a) Folded dipole antenna has less impedance than half dipole
b) Folded dipole is a balanced antenna
c) Folded dipole antenna is a dipole antenna with its end folded back forming a loop
d) Balun is used at the feeder when unbalanced feed is used in the folded dipole
Explanation: The impedance of folded dipole is four times the impedance of the half dipole. So its impedance is higher than the half dipole. Since folded dipole is a balanced antenna we use a balanced feeder so Balun is used.
10. Folded dipole antenna belongs to which type of antenna?
a) Reflector
b) Aperture
c) Lens
d) Wire
Explanation: Folded dipole antenna belongs to wire antenna. It is a dipole antenna with two ends folded back and connected to each other forming a loop.