This set of Antennas Multiple Choice Questions & Answers (MCQs) focuses on “Phased Array – Fed Types”.
1. Phase array with lens array come under which feeding system?
a) Optical-feed system
b) Constrained feed system
c) Sub array feed
d) Phase shifter
View Answer
Explanation: Phased array with lens or reflector arrays comes under the optical feed system. Proper aperture illumination is obtained by the optical feed system. In constrained the power is divided into many elements under different steps.
2. Which of the following statement is true?
a) Lens array has different input and output radiators while same radiator is used for reflector array
b) There is no surface matching required for the lens array
c) In lens and reflect array same radiator is used for input and output
d) Lens and reflect array belong to constrained feed systems
View Answer
Explanation: In Lens array, different input and output radiators are used and hence there two surface matching is required. In reflect array the same radiator is used to radiate and collect.Phased array with lens or reflector arrays comes under the optical feed system.
3. In which of the following feed system, the power division among elements on aperture is done in several steps?
a) Constrained feed systems
b) Optical feed systems
c) Lens array
d) Reflect array
View Answer
Explanation: The power is divided into many elements under different steps in constrained feed systems. Phased array antennas with lens or reflector arrays belong to the optical feed system. Proper aperture illumination is obtained through the optical feed system and systems power is divided in one step.
4. Which of the following series feed has same bandwidth similar to parallel feed network?
a) End fed array
b) Center fed array
c) Both end fed and Center fed array
d) Neither End fed nor center fed array
View Answer
Explanation: The Center fed array in the series feed network has same bandwidth as the parallel feed networks. The end fed array has several bandwidth restrictions.
5. In which of the following the feed is provided at the end of the array?
a) Series end fed
b) Series center fed
c) Parallel feed
d) Optical feed systems
View Answer
Explanation: In series end fed, the radiator is placed at the end of the array and its electrical path length depends on the frequency. In center fed, radiator is provided at the center of the array and has bandwidth similar to the parallel feed network. In parallel feed, a number of radiators are combined into sub-arrays and then to elements in series or center fed.
6. In which of the following radiators are combined into sub-arrays and then fed to elements in end or center fed?
a) Parallel feed
b) Series feed
c) Optical feed system
d) Series end feed
View Answer
Explanation: In parallel feed, a number of radiators are combined into sub-arrays and then to elements in series or center fed. In series end fed, the radiator is placed at the end of the array and its electrical path length depends on the frequency.In optical feed systems power is divided in one step.
7. In which of the following the power is divided in single step among the elements?
a) Optical feed system
b) Constrained feed system
c) Parallel feed system
d) Sub-array
View Answer
Explanation: Proper aperture illumination is obtained by the optical feed system. In constrained the power is divided into many elements under different steps. In optical feed systems power is divided in one step. In parallel feed, a number of radiators are combined into sub-arrays and then to elements in series or center fed.
8. The power divider used to connect array elements to single port is called _____
a) array feed
b) phase shifter
c) frequency shifter
d) repeater
View Answer
Explanation: The power divider used to connect array elements to single port is called array feed. Array feeds are classified into three types: Constrained feeds, Optical feed/ space feed, parallel plate feed.
9. Which of the following feed techniques the reflect array used particularly?
a) Space feed
b) Constrained feed
c) Parallel plate feed
d) Sub array
View Answer
Explanation: In space feed, the energy is distributed to the lens array in a manner analogous to point feed illuminating a reflect antenna. In constrained the power is divided into many elements under different steps. In optical feed systems power is divided in one step. Parallel plate feed uses microwave structure principles and provides efficient power division.
10. A folded pillbox antenna is used in which of the following feeding system?
a) Parallel plate feed
b) Space feed
c) Optical feed system
d) Constrained feed system
View Answer
Explanation: Folded pillbox antenna is used to provide the power distribution to antenna elements. So this is used in the parallel plate feed system. Lens and reflect array used in the space/optical feed systems. Constrained feed provides a series and parallel feed combination.
11. Parallel plate feed is a cross of constrained and space feed.
a) True
b) False
View Answer
Explanation: Parallel plate feed uses microwave structure principles and provides efficient power division.In constrained the power is divided into many elements under different steps. In optical feed systems power is divided in one step. In space feed, the energy is distributed to the lens array.
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