Kerala University 2006 B.Tech Electronics and Communications Engineering SIXTH SEMESTER /E (2003 Scheme) :ANTENNA AND WAVE PROPOGATION - Question Paper

SIXTH SEMESTER B.TECH DEGREE EXAMINATION

MAY/JUNE 2006 (2003 Scheme)

03.605:ANTENNA AND WAVE PROPOGATION (T)

 

Time : 3 Hours Max.Marks : 100

 

PART A

 

Answer all questions .Each Question carries 4 marks

 

1. What is effectiveness ratio of an antenna?
2. Explain on fields regions of an antenna?
3. What is antenna efficiency?
4. A uniform plane wave is incident on a short lossless dipole. Find its effective aperture?
5. What are the different types of feed used in dish antenna?
6. What are the different methods used for measurement of diversity?
7. What is optimum working frequency?
8. What is Secant Law?
9. Explain LOS propagation?
10. Define terms
• Critical frequency
• Virtual height

 

 

Part B

 

Module I

 

11. a) Explain the concept of retarded potential?

b) Derive expression for field regions of an antenna?

12. Derive expression for effective area of an antenna. How is it related to directivity of the antenna?
13. Derive the radiation resistance of λ/2 antenna?

 

Module II

14. Draw the diagram and explain the working of log periodic antenna?
15. a) What is pattern multiplication?

b) Find the radiation pattern of 4 isotropic demerits fed out of phase and spaced

λ/4 apart?

16. Explain in detail the measurement of beam width of an antenna?

 

Module III

 

17. Derive expression for modified refractive index of ionosphere
18. a) Explain ELF propagation in sea water?

b) A λ/2 transmitting antenna radiates 10Kw of power at 100MHz. If the heights

of the transmitting and receiving antenna are 100m and 9m respectively

calculate (i) the radio horizon range and (ii) field strength at 10km from the

transmitting antenna.

19. a) Explain the method of virtual height measurement with neat diagram.

b) Write notes on Faraday rotation in ionosphere.