Important RGPV Question
EX- 603 (C) Electromagnetic Waves
VI Sem, EX
UNIT 1- Transmission Lines
Q.1) Explain lossless and low loss transmission lines.
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Q.2) Discuss analysis of transmission line in terms of admittance.
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Q.3) Describe impedance matching using transmission lines.
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Q.4) Write the name of two impedance matching techniques used in Transmission lines.
Q.5) If the length of a transmission line is less than λ/4 then draw its electrical equivalent circuit.
Q.6) Define the characteristic impedance of a Transmission line and find its value at 50MHz. Assume the line primary parameters per unit length are R = 0.2 ohm, L= 0.2 Nanohenery, C=0.5 nanofarad and G=10 Mho.
Q.7) Design a single stub of a Transmission line which is terminated with a load of 20+j50 ohm and has characteristic impedance Z₀ = 100 ohm. Assume the signal frequency is 100 MHz.
Q.8) Explain the different losses in Transmission line and compare them a) in different type of Transmission line and b) at different frequency. How these losses can be reduced?
Q.9) Define the reflection and transmission coefficient and find their value in following cases:
a) A Transmission line (with Z0 = 100) terminated with ZL = 200 + j 10
b) A Transmission line (with Z0 = 100) terminated with ZL = j 100
c) A Transmission line (with Z0 = 100) terminated with open circuit.
Q.10) Find the expression of input impedance of a Transmission line in terms of its characteristic impedance, load impedance and length of the line. Also find the value of it when the line length is
a) l=2λ and ZL=0 ohm and b) l=λ/4 and ZL=Z0.
UNIT 2- Maxwell’s Equations
Q.1) Write and explain Ampere’s circuital law with its applications.
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Q.2) What is a surface charge and surface current?
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Q.3) Write down and explain Maxwell’s equations in point form and integral form.
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Q.4) Write the Maxwell equation in differential form for electric field which determine the pattern of electric flux line.
Q.5) Why TEM mode is not possible inside waveguide explain the reasons supporting with Maxwell’s equations.
Q.6) Explain boundary conditions of electric and magnetic field. How these conditions are used?
Q.7) Write all Maxwell equations in integral form for a dynamic EM field for vacuum and a lossy medium. Using these also develop the EM wave equation find prove that in vacuum the Wave are Transverse in nature.
UNIT 3- Uniform Plane Wave
Q.1) State and prove poynting theorem.
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Q.2) What is mean by polarization of a wave? When wave is linearly polarized? When wave is circularly polarized?
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Q.3) Write the unit of pointing vector.
Q.4) If the group velocity is 0.9×10⁸ m/s then find the corresponding phase velocity.
UNIT 4- Plane Waves At Media Interface
Q.1) Discuss reflection and refraction of waves at dielectric interface.
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Q.2) What is lossy media interface? How it improved?
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UNIT 5- Waveguides
Q.1) Explain parallel plane waveguide? Discuss Transverse Electric (TE) mode, Transverse Magnetic (TM) mode, Transverse Electromagnetic (TEM) mode.
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Q.2) If the cutoff frequency of an air-filled waveguide is 10 GHz and support TE, mode then what is its size?
Q.3) If cutoff frequency of TE₁₁ mode is 5 GHz then find the operating frequency of TE₂₃ mode.
Q.4) Write the general expression of waveguide impedance when TM mode propagating inside waveguide.
Q.5) The cross section of a rectangular waveguide is 20×40 cm² then find the operating frequency of a) TE₀₂ and b) TE₃₂ mode.
Q.6) Draw the electric and magnetic field pattern inside a waveguide at a) TE₁₀ and b) TM₂₁.
Q.7) Explain the working of rectangular waveguide. What is the frequency range where these waveguide are most suitable? Find the minimum cutoff frequency of a waveguide, also find it for a waveguide whose cross section is 25×50cm².
Q.8) Explain a) How microstrip lines are better than Waveguide at and above 60 GHz b) How Waveguides are better than microstrip lines between 1 to 30 GHz.
UNIT 6- Antennas
Q.1) What are the radiation parameters of antenna? Describe
potential function.
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Q.2) Discuss radiation resistance and radiation pattern of Hertz dipole.
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Q.3) Define the radiation resistance of an antenna.
Q.4) Explain any four antenna parameter and also write their units.
Q.5) Draw the 2D and 3D radiation pattern of a dipole and mono pole antenna.
Q.6) How EM signal radiated from a conductor? What are the conditions for it? Define the far field and near field around a radiating current element. Also find the interrelation between these two fields.
Extra Questions-
Q.1) Write short note on any two of following.
a) Gauss law
b) Uniform plane wave in dielectrics
c) Transmission line calculations with the help of smith chart
d) Brewster angle
(RGPV Dec 2020)
— Best of Luck for Exam —
