SRM University 2007 B.Tech Electronics and Communications Engineering Bank : Antennas and Wave Propagation - Question Paper

7. What is a Yagi – Uda array ?
8. State Babinet’s principle.
9. Why is flaring needed in Horn antennas ?
10. What is primary radiation and secondary radiation as applicable to parabolic reflector ?
11. What is the cause for using Yagi antenna for TV broadcast reception ?
12. What are the applications of Yagi – Uda antenna ?
13. What are parasitic elements and where are they used ?
14. How does a parabolic reflector give very high gain ?
15. What is a parasitic element ? How does it act when length is greater than and smaller than ? / two ?
16. What is cheese feed as applicable to parabolic reflectors ?
17. Mention the antennas used in medium frequency range .
18. How is a high frequency dipole antenna fed and matched with driving source ?
19. Sketch the diagrams of different kinds of Horn antennas.
20. What are Traveling wave antennas ?
21. Distinguish ranging from resonant antenna and TWA ?
22. Distinguish ranging from standing wave antenna and TWA ?
23. Define Spill over.
24. What is meant by smart antenna ?
25. What is the principle of microwave antenna ?
26. Define pitch angle. When a = 0o and a = 90o, how does the helical antenna behave ?
27. What are the parameters to be considered in the design of an helical antenna ?
28. What are the various modes of operation that can be used in Helical antenna ?
29. List the applications of Helical antenna.
30. Why does the normal mode of operation is not preferred in Helical antenna ?
31. Draw the structure of an Helical antenna with its parameters.
32. What is Cassegrain feed mechanism ?

PART - B

1. Explain the principle of traveling wave radiator.
2. Derive an expression for the radiated field due to a TWA.
3. Obtain the expression for the field produced by TWA and compare its radiation with resonant antenna.
4. Obtain the expression for the emf due to loop antenna and discuss its use as a Direction finder.
5. Explain the special features of different kinds of Horn antennas and frequency independent antennas.
6. With a suitable diagram, explain the construction and operation of a Yagi antenna.
7. Write detailed notes on (a) Parabolic reflectors (b) Log Periodic antennas
8. (a) discuss the principle of operation and applications of folded dipoles.
(b) With a suitable diagram discuss the construction and principle of operation of a log – periodic antenna.
9. Write short notes on (a) Slot radiators (b) Loop antennas

Earning:   Approval pending.