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

S.R.M. Institute of Science & Technology
Deemed University
School of Electronics & Communication Engineering

ques. Bank
Subject Code : EC401
Subject Name : Antennas and Wave Propagation
Year & Sem : IV Year B.Tech (ECE) ,7th Sem.

UNIT-I
PART-A
1. Define Isotropic radiator.
2. Calculate the directivity of an Isotropic antenna.
3. Differentiate Radian & Steradian.
4. Define Gain & Beam width of an antenna.
5. Derive an expression for effective aperture area of antenna.
6. Calculate the maximum effective aperture area of antenna which is operating at a wavelength of two meters and has a directivity of 100.
7. Define Antenna Efficiency.
8. Write note on radiation trend.
9. What is radiation intensity and discuss in terms of poynting vector?
10. Explain directivity of an antenna.
11. Find out the radiation resistance of a ?/16 wire dipole in free space.
12. Define power gain and write down the relation ranging from directive gain and power gain.
13. Define radiation resistance and write down the expression for it.
14. Differentiate antenna bandwidth and beam width.
15. Define beam solid angle and antenna beam efficiency.
16. An antenna has a radiation resistance of 72 Ohms, a loss resistance of eight Ohms and a power gain of 12dB. Determine the antenna efficiency and its directivity.
17. Define Terminal impedance.
18. State reciprocity theorem and briefly discuss it.
19. Calculate the radiation resistance of short dipole.
20. Calculate a maximum effective aperture of a half wave dipole.
21. Calculate the length of a half wave dipole antenna meant to have accurate half wave length at 60 MHz.
22. Calculate the maximum effective aperture of a microwave antenna which has a directivity of 900.
23. Calculate the radiation resistance of an antenna which is drawing 15A current and radiating five KW.
24. Calculate the power being radiate by an antenna having a radiation resistance of 50 Ohms and is drawing a current of 8A.
25. Calculate the radiation resistance of an antenna which is radiating 1000W and drawing current of 5A.
26. How much current does an antenna draw when radiating 1000W and is having a radiation resistance of 300 Ohms.
27. Mention the radiation and Induction field component for a small current element.
28. Show the directivity of an electric current element 3/2.
29. Define poynting vector.
30. What is effectiveness ratio?
31. What is scattering loss aperture?
32. Define effective length of an antenna.

PART - B
1. Explain the retarded vector potential in detail.
2. Derive an expression for the power radiated by the current element and compute the radiation resistance.
3. Derive an expression for the far field component of a half wave dipole of an antenna.
4. a) Derive the total power radiated by half wave dipole.
b) Show that the radiation resistance of a half wave dipole is 80?2 (dl/?)2 Ohms.

Earning:   Approval pending.