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Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SIXTH SEMESTER B.TECH DEGREE EXAMINATION, APRIL 2018
Course Code: EC306
Course Name: ANTENNA AND WAVE PROPAGATION (EC)

Max. Marks: 100 Duration: 3 Hours
PART A
Answer any two full questions, each carries 15 marks. Marks
1 a) State and Prove Reciprocity Theorem as applied to Antennas. (8)
b) Explain the concept of retarded potentials. (4)
c) Define Antennae Temperature. (3)

2 a) Derive expressions for the Far Field components and Radiation Resistance of a (12)

half wave dipole.

b) Define Gain and Directivity of an antenna. (3)
3 2) Derive expressions for beam solid angle in terms of Directivity of an Antenna. (4)
b) Distinguish between Effective Aperture and Physical Aperture of an antenna. (4)

c) Draw an experimental setup and explain how radiation pattern measurement ofan (7)
antenna is carried out.
PART B
Answer any two full questions, each carries 15 marks.
4 a) State the Principle of Pattern multiplication. Explain and illustrate the principle (7)
with an N element array.
b) With a neat diagram explain the principle of operation of a Horn antenna (4)
c) Explain the importance of Cassegrain Antennae. (4)
5 a) Derive expressions for array factor of an N element linear uniform array and (6)

obtain its maximum value.

b) Explain the construction and working of Rhombic Antenna (6)
c) Explain the basic Principle of Beam Steering. (3)
6 a) Design a broadside Dolph —Tschebyscheff array of 8 elements with spacing of (10)

d= 2/2 between the elements and major to minor lobe ratio of 25 dB.
b) Derive expressions and plot the pattern for the field radiated by two isotropic (5)

point sources fed with current of same magnitude and phase.

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