Electromagnetic Engineering - December 2014

MU Electronics Engineering (Semester 5)

Total marks: --
Total time: -- INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Answer the following any four:

1 (b) Derive wave equations for time harmonic fields. 5 marks

1 (c) The radiation resistance of antenna is 72Ω and the loss resistance is 8Ω. Calculate its directivity in dB if the power gain is 16. 5 marks

1 (d) Explain the important advantages and drawback of FDM. 5 marks

1 (e) Define critical frequency, MUF and OWF. 5 marks

2 (a) State and Explain Maxwell's equations in differential and internal form for static field. 5 marks

2 (b) A 10 GHz plane wave traveling in free space has an amplitude of E_x=10V/m. Find
i) The phase constant
ii) Intrinsic impedance and
iii) The amplitude and the direction of H. 5 marks

2 (c) Explain the operating modes of helical antennas. 5 marks

3 (a) Explain the mechanism of ionospheric propagation. A high frequency radio link has to be established between two points at a distance of 2000 km. On the earth's surface. Considering the height of 200km and critical frequency of 5MHz. Calculate MUF for given path. 5 marks

3 (b) Derive an expression for radiation resistance of an infinitesimal dipole antenna and explain its significance. 5 marks

3 (c) Derive Laplace's and Poisson's equations. 5 marks

4 (a) Find the transmission and reflection coefficients at the boundary for normal incidence. Given that for region 1:?_r1=1, &insin;_r1=9 and for region 2 is a free space. Consider the perpendicular polarization. 5 marks

4 (b) Derive an expression for vector magnetic potential wave equation. 5 marks

4 (c) Explain the physical significance of the terms α, β and γ related to wave propagation in lossy dielectrics. 5 marks

5 (a) Give the comparison of FDM, FEM and MOM. 5 marks

5 (b) Determine the poynting vector and explain the power flow terms due to the time varying fields. 5 marks

5 (c) The height of monopole antenna is ?/100 what is the radiation resistance. 5 marks

Write a short notes on:-

6 (b) Polarization of waves. 5 marks

6 (c) Antenna parameters. 5 marks

6 (d) Space wave propagation. 5 marks