## Wave Theory & Propagation - Dec 2014

### Electronics & Telecomm. (Semester 4)

TOTAL MARKS: 80

TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.

(2) Attempt any **three** from the remaining questions.

(3) Assume data if required.

(4) Figures to the right indicate full marks.

### Attempt any four out of the five:-

**1 (a)** Write integral from of Amperes Law and interpret the same.(5 marks)
**1 (b)** Define Intrinsic Impedance. Calculate its value for free space.(5 marks)
**1 (c)** Give and explain various steps involved in finding characteristics impedance for micro-strip line using finite difference Method.(5 marks)
**1 (d)** What do you mean by Depth of pentration.(5 marks)
**1 (e)** What is loss Tangent. Explain how it classifies lossless dielectrics, lossy Dielectric and good conductor.(5 marks)
**2 (a)** Derive Maxwells equation in point form and integral form.(10 marks)
**2 (b)** Compare FDM, FEM & MOM.(5 marks)
**2 (c)** Compare scalar and vector potential.(5 marks)
**3 (a)** In certain Medium [ ar{E}= left [ 10e^{-0.05x} sin left ( 2 imes 10^8 t-2x
ight )
ight ]ar{a}_2 v/m Find: ]

i) Propagation constant

ii) Wavelength

iii) Speed of wave

iv)Skin Depth(10 marks)
**3 (b)** Derive wave equation for good dielectric medium.(5 marks)
**3 (c)** Give Boundary conditions for Electric and magnetic field for interface between good conductor and dielectric.(5 marks)
**4 (a)** Use method of moment to find the capacitance of parallel plate capacitor of figure 1. Take a=1 meter; b=1 meter; d=1 meter and &epsilon_{r}=1.
(10 marks)
**4 (b)** Derive an expression for magnetic field intensity due to finite long straight element.(10 marks)
**5 (a)** What do you mean by Fading? How it can be minimized?(5 marks)
**5 (b)** Write a short note on Ionospheric Propagation.(5 marks)
**5 (c)** Explain Super Refraction and Tropospheric Fading.(10 marks)
**6 (a)** Prove that static electric field is irrotational ans static magnetic field solenoidal.(10 marks)
**6 (b)** Explain Reflection of Uniform Plane wave at Oblique Incidence.(10 marks)