Roll No.: Part - B (5 X 1 6 80 Marks)
Roll No.: Part - B (5 X 1 6 80 Marks)
Roll No.: Part - B (5 X 1 6 80 Marks)
Part - B ( 5 x 1 6 = 80 marks)
11
(i)
(12)
(ii) A resonant half wavelength dipole is made out of copper (a =5.7 x 10 S/m) wire.
Determine the radiation efficiency of the dipole antenna at f=75 MHz if the radius of
the wire b is 2 x 10" A, and the radiation resistance of the A/2 dipole is 73 ohms. (4)
7
(16)
(OR)
12 b (i)"A horn antenna may be regarded as a flared out or opened out waveguide".
Substantiate and elaborate. Derive the expression for L of a horn antenna.
(ii)Elaborate on reflector antennas.
(8)
(8)
Roll No.
13.
a)
(i)Explain in detail the Binomial array.Sketch the Pascal's triangle upto m=7. (10)
(ii)Discuss in detail the design of a broadside array.
(6)
(OR)
14.
b)
(i)Arrive at the array factor of a two-element array.For this array, find the nulls of
(12)
the total field when d = A/4 and the cases of (3=0, (3 =90 and p= -90.
(ii)Define(i)Uniform array (ii) Grating lobes.
(4)
a)
(6)
(6)
(4)
(OR)
15.
b)
a)
(i)Discuss in detail about the structure of atmosphere and the different modes of
propagation.
(12)
(ii)Define(i)Virtual height (ii)Critical frequency
(4)
(OR)
b)
(i)Write short notes on (i) Sky wave propagation and (ii) Flat earth and Curved
earth concept.