Types of Antenna MCQs : Here you will find MCQ Questions related to "Types of Antenna" in Avionics. These Types of Antenna MCQ Questions Will help you to improve your Avionics knowledge and will prepare you for various Examinations like Competitive Exams, Placements, Interviews and other Entrance Exmaniations
Question 1
Which of the following is a hypothetical antenna that radiates equal signal power in all directions?
A. Dipole
B. Isotropic
C. Monopole
D. All of the above
View Answer
Ans : B
Explanation: An isotropic antenna (isotropic radiator) is a hypothetical antenna that radiates equal signal power in all directions.
Question 2
In Turnstile, Two dipole antennas mounted at right angles, fed with a phase difference of?
A. 45 degree
B. 75 degree
C. 90 degree
D. 120 degree
View Answer
Ans : C
Explanation: Turnstile : Two dipole antennas mounted at right angles, fed with a phase difference of 90°.
Question 3
Corner reflector : A directive antenna with moderate gain of about _________ often used at UHF frequencies.
A. 5 dBi
B. 6 dBi
C. 7 dBi
D. 8 dBi
View Answer
Ans : D
Explanation: Corner reflector: A directive antenna with moderate gain of about 8 dBi often used at UHF frequencies.
Question 4
biconical antenna is a dipole-like antenna made of two cones, oriented along the same axis and oriented tip-to-tip.
A. TRUE
B. FALSE
C. Can be true or false
D. Can not say
View Answer
Ans : A
Explanation: True, biconical antenna is a dipole-like antenna made of two cones, oriented along the same axis and oriented tip-to-tip.
Question 5
Butterfly antenna is a ________ dimesional (flat) biconical antenna.
A. multi
B. two
C. one
D. All of the above
View Answer
Ans : C
Explanation: Butterfly antenna is a two-dimesional (flat) biconical antenna.
Question 6
Discone antenna is full of a biconical with a flat disc mounted below the cone
A. TRUE
B. FALSE
C. Can be true or false
D. Can not say
View Answer
Ans : B
Explanation: Discone antenna is half of a biconical with a flat disc mounted above the cone.
Question 7
The impedance at the center of the antenna is known as?
A. Characteristic impedance
B. Recovery resistance
C. Transmission impedance
D. Radiation resistance
View Answer
Ans : D
Explanation: The transmission line is connected at the center. The dipole has an impedance of 73 V at its center, which is the radiation resistance. At the resonant frequency, the antenna appears to be a pure resistance of 73 V.
Question 8
What is the use of loading coil?
A. Correcting resonance to a desired frequency
B. Increasing the antenna gain
C. Sideband suppression
D. Increasing the range of the antenna
View Answer
Ans : A
Explanation: When a vertical antenna is made less than one-quarter wavelength, the practical effect is a decreased inductance. The antenna no longer resonates at the desired operating frequency, but at a higher frequency. To compensate for this, a series inductor, called a loading coil, is connected in series with the antenna coil. The loading coil brings the antenna back into resonance at the desired frequency.
Question 9
The type of dipole antenna that has a higher band width is called as?
A. Yagi antenna
B. Helical antenna
C. Conical antenna
D. Marconi antenna
View Answer
Ans : C
Explanation: A common way to increase bandwidth in the antenna is to use a version of the dipole antenna known as the conical antenna. The overall length of the antenna is 0.73λ or 0.73(984)/f = 718.32/f. This is longer than the traditional one-half wavelength of a dipole antenna, but the physical shape changes the necessary dimensions for resonance.
Question 10
Why is top hat added to antennas?
A. To increase capacitance
B. Increasing the antenna gain
C. Sideband suppression
D. Increasing the range of the antenna
View Answer
Ans : A
Explanation: A top hat is a structure that increases the capacitance to surrounding items, bringing the antenna back into resonance. Obviously, such an arrangement is too top-heavy and inconvenient for portable and mobile antennas. However, it is sometimes used in larger fixed antennas at lower frequencies.