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

5. Explain the reciprocity theorem in detail.
6. Derive an expression for the electric field and magnetic field due to a current element at a distance point in free space.
7. a) Derive an expression for the gain of half wave dipole.
b) discuss effective aperture area with its kinds in detail.
8. At what distance in ?, is the radiation component of magnetic field twice the inductance component ? At what distance is it 100 times.



UNIT –II – Antenna Arrays
PART - A
1. What is an array and mention the different forms of antenna arrays?
2. What is a uniform linear array?
3. What is Broad side array and draw its radiation pattern?
4. What is End fire array and draw its radiation pattern?
5. What is collinear array?
6. What is parasitic array?
7. What is trend multiplication concept?
8. List a few of the advantages of trend multiplication.
9. What is tapering of array?
10. Write a note on Binomial array.
11. How the secondary lobes are eliminated?
12. What is Pascal’s triangle?
13. What is a Phased array?
14. What is a smart antenna?
PART-B
1. Write short notes on different forms of arrays
i.Broad side array ii.End fire array
iii.Collinear array iv.Parasitic array

2. Derive the expression for the far field trend of an array of two – isotropic point sources
i) Equal amplitude and phase
ii) Equal amplitude and opposite phase
iii) Unequal amplitude and any phase

3. Explain the principle of trend multiplication.

4. Explain the array of N- sources of equal amplitude and spacing- Broad side case
i. Direction of trend maxima ii. Direction of trend minima
ii. Beam width of major lobe

5. Explain the array of N- sources of equal amplitude and spacing- End fire case
i) Direction of trend maxima ii. Direction of trend minima
ii) Beam width of major lobe

6. Write short notes on
i. Binomial arrays ii. Phased arrays







UNIT-III - SPECIAL PURPOSE ANTENNAS
PART-A
1. What are the applications of loop antenna ?
2. Give the cause for poor radiation of a loop antenna .
3. Distinguish ranging from sectorial and pyramidal Horn antenna.
4. What are the advantages of folded dipole ?
5. What is a folded dipole ? elaborate its important properties ?
6. Draw the structure of Log- periodic antenna.

Earning:   Approval pending.