 MORE IN Electromagnetics and Transmission Lines
SPPU Electronics and Telecom Engineering (Semester 5)
Electromagnetics and Transmission Lines
May 2017
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

Solve any one question from Q.1(a,b,c) &Q.2(a,b,c)
1(a) Derive the expression for electric filed intensity $$\bar{E}$$/ at a point 'P' due to infinite line charge with uniform line charge density 'ρ' L.
6 M
1(b) Derive the electrostatic boundary condition between two dielectric media.
8 M
1(c) Find $$\bar{H}$$/ at point P(2, 3, 4) caused by a current filament of 12A in a $$\hat{a_{y}}$$/ direction on y axis and extending from y = 0 to y = 8.
6 M

2(a) Derive relation between $$\bar{E}$$/ and V. Also state significance to potential gradient.
8 M
2(b) Find the capacitance of parallel plate capacitor containing two dielectrics, $$\varepsilon _{r1}=1.5 \ \ \text{and}\ \ \varepsilon _{r2}=3.5,$$/ each comprising one half the volumes as shown in figure. Here area of plates A = 2m2 and d = 10-3 m.
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6 M
2(c) State and prove Ampere's Law and apply the same for infinite sheet of current.
6 M

Solve any one question from Q.3(a,b) &Q.4(a,b)
3(a) Write Maxwell's equations for static and time varying fields in point and integral forms.
8 M
3(b) State and prove Poying theorem. Interpret each them.
8 M

4(a) What do you mean by uniform plane wave? Obtain equation of wave travelling in free space in terms of $$\bar{E}$$/.
8 M
4(b) The magnertic filed of an EM wave in free space is given by $$\vec{H}=0.5\epsilon _{0}\cos \left ( \omega t-100z \right )\hat{a}_{y}\frac{A}{m}.$$/ Findthe electric field intensity and displacement current density.
8 M

Solve any one question from Q.5(a,b) &Q.6(a,b)
5(a) State primary and secondary constants of transmission lines. Derive the relationship between primary and secondary constants of transmission line.
8 M
5(b) The characteristic impedance of the uniform transmission line is 2040Ω at a frequency of 800Hz, At this frequency, the propagation constant is 0.054 ∠ 87.9°. Determine R, L. G, C, α and β
8 M

6(a) Explain the phenomenon of reflection of transmission line and hence defien reflection coefficient.
8 M
6(b) Derive the expression for characteristic impedance (Z0 and propagation constant in terms of primary constants of transmission lines.
10 M

Solve any one question from Q.7(a,b) &Q.8(a,b)
7(a) What is impedance matching? Explain necessity of it. What is stub matching? Explain signle stub matching with merits and demerits.
10 M
7(b) A 50Ω line is terminated by a load impedance of (75 - j69) Ω. The line is 3.5 meter long and is excited by 50 Mhz source. Propagation velocity is 3×108m/sec. Find the input impedance, reflection coefficient, VSWR, position of minimum voltage.
8 M

8(a) What is mean by distortionless line? Derive the expression for characteristic impedance and propagation constant for it.
10 M
8(b) A transmission line has a characteristic impedance of 300Ω and terminated n a load ZL = 150+j150Ω. Find the following using smith chart.
i)VSWR
ii) Reflection Coefficient.
iii) Input impedance at a distance 0.1λ from load.