# Antennas and Wave Propagation EC2353 MJ2014 6th Semester Question Paper

Anna University Question Paper
B.E./B.Tech. DEGREE EXAMINATION, May /June 2014.
Electronics and Communication Engineering
3rd year
6th Semester
EC2353/EC 63/10144 EC604-Antennas and Wave Propagation

Part A

1. What is the significance of radiation resistance of an antenna?
2. Draw E and H plane radiation pattern of a dipole.
3. Compare short dipole from half wave dipole.
4. What are the advantages of antenna arrays?
5. What is called method of imaging?
6. State field equivalence principle.
7. Why frequency independent antennas are called so?
8. Mention any two applications of turnstile antenna.
9. Differentiate virtual height from actual height.
10. What are the effects of ground on low frequency wave transmission?

Part B

11 a)1] Define the following parameters and their dependence on antenna performance.
2] Derive the magnetic field components of a dipole having the dimension l<<â„“/2(8)
Or
b) 1] Explain the terms 1)Beam solid angle,2)Antenna temperature,3)Reciprocity principle.(8)
2] Derive the current and vector potential of a hertizian dipole(8)

12 )a) Derive the electric and magnetic field components of a finite length dipole antenna and show its current distribution with respect to its length in terms of wavelength.(16)
Or
b) 1) Derive the expression for the field produced by a linear array and deduce it for an end fire array.(10)
2) Compare end fire and broadside array.(6)

13) a)1]Explain the principle of rectangular horn antenna with neat sketch.(8)
2] Explain the salient features of flat and corner reflector antenna.(8)
Or
b) With neat diagram explain the principle of parabolic reflector antenna and various types of feed used.(16)

14) a)1]Explain the measurement of antenna gain(8)
2] With necessary illustrations explain the radiation characteristics of Yagi Uda antenna.(8)
Or
b) With suitable diagram explain the construction and principle of Helical antenna in different mode of operation.(16)

15)a)1]Explain the ground wave propagation of radio waves(8)
2] Write notes on faraday rotation.(8)
Or
b) 1]Describe the space wave propagation and explain the importance of line of sight propagation.(8)
2] Explain the following terms with diagram
1) Duct propagation,2)Critical frequency,3)Skip Zone.