# Antennas Questions and Answers – Polarization Mismatch

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This set of Antennas Multiple Choice Questions & Answers (MCQs) focuses on “Polarization Mismatch”.

1. What is the polarization loss factor due to mismatch if the two linear polarized antennas are rotated by an angle ∅?
a) tan⁡∅
b) cos⁡∅
c) cos2
d) cos-1⁡∅

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∅.

2. What is the polarization loss factor when a linear polarized antenna receives a circular polarized?
a) 0.5
b) 1
c) 0
d) 2

Explanation: Circular polarization is combination of two orthogonal linear polarized waves at 90° phase difference. The linear component just selects one in-phase component from this so ∅=45
⇨ PLF = cos2∅.=1/2=0.5

3. 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=$$\frac{3}{4}=0.75$$

4. 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∅.

5. 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∅.

6. 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

7. 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

8. 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.

9. 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∅.

10. 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