Anna University

ANTENNA AND WAVE PROPAGATION 2012 Important Questions

Subject Code : EC2353

Subject Name : ANTENNA AND WAVE PROPAGATION

Unit 1
1.State and Elaborate Reciprocity Theorem and Explain the various application of reciprocating theorem.

2.State and Derive the wave Equation in terms of electromagnetic potential.

3.Derive the expression for the power radiated by the current element and calculate the radiation resistance.

4.Explain in detail about i) Beam width and HPBW

ii)Polarization

iii) Effective Aperture area

iv)Hertzian Dipole.

5. Obtain the relation between effective aperture and directivity.

Unit 2
1.In a linear array of 4 isotropic elements spaced ¥/2 apart and with equal current fet in phase , plot the radiation pattern.

2.Derive the radiation resistance of a small loop in terms of its circumference.

3. Obtain the expression for the power radiated by a half wave dipole .

4.Derive the field components and rms power radiated from half wave dipole .Calculate the radiation resistance of a half wave dipole.

5.Draw the radiation pattern of array of two point source with equal amplitude and opposite phase by calculating the maximum , minimum and half power points directions.

Unit 3
1.Explain how E-plane type metal plate lens antenna are developed and derive expression for spacing between plates equation of ellipse.

2.Discuss and write in detail about the application of slot , Horn ,Reflector , and Lens Antenna.

3.Derive the expression for the shape of the lens and the reflective index in the case of dielectric lens antenna.

4.Write short notes on pattern properties.

Unit 4
1.What is biconical antenna ?Drive the expression for the radiated fields of a biconical antenna.

2.Describe how the radiation pattern of a given antenna can be measured experimentally.

3.Explain the construction and working principle of Yagi – Uda antenna.

4.With neat sketch , explain the construction and working principle of helical antenna.

Unit 5
1.Drive and expression to calculate the height of the propagating radio wave as a function of distance.

2.Explain how to calculate the grade circle distance between any t points on the Earth.

3.Explain in detail about the modes o propagation.

4.Explain in detail about the skip distance and virtual height.