SRM University 2007 B.Tech Electronics and Communications Engineering BANK : TRANSMSSION LINES AND WAVES GUIDES - Question Paper

3. Give the expression for cut-off frequency for TE Mode.
4. What is the cut-off wavelength for the TE10 mode?
5. A rectangularA rectangular Wave Guide is 2-5cm X 5cm in dimensions. compute the cut-off wavelength for TE10 mode.
6. Define Guide Wavelength.
7. What is phase velocity?
8. Why are waveguides not preferred at low frequencies?
9. Why is the dominant mode of propagation preferred with rectangular Wave Guide.?
10. State any 2 characteristics of TEM waves.
11. Mention which of the subsequent transmission line / Wave Guide will carry the largest power?
a) Coaxial b) Wave Guide c) Open Wire Line
12. Can a a TmM01 (or) TM10 mode exists for a rectangular Wave Guide? Justify
13. What is a waveguide?
14. What are the transverse electric (TE) Waves?
15. What are the transverse magnetic (TM) Waves?
16. Find the frequency of minimum attenuation for TM mode.
17. Define dominant mode in a Wave Guide.
18. Write down the relation ranging from guide wavelength, free space wavelength and Cut-off wavelength.
19.What is a TE Wave?
20.19. Write down Maxwell’s equations.
21.20. For the TM mode ranging from parallel planes, Write down an expression for the frequency at which the attenuation is a minimum.
22.21. Mention the advantages and disadvantages of circular Wave Guide.


Part - B

1. A 4GHZ signal is propagated in a rectangular Wave Guide with internal dimensions of five X 2.5 cm. Assuming the dominant mode, compute.
a) Cut-off wavelength b) Guide Wavelength
c) Group Velocity d) Phase Velocity

2. Obtain the field components of the wave propagating ranging from parallel planes.

3. Discuss the propagation of TE waves in a rectangular Wave Guide. Derive the general relationship which connects free space wavelength, guide wavelength and critical wavelength.

4. a) Derive the EM field expression for TM Waves guided by a parallel plane perfectly conducting structure.
5. Derive the field expressions for TE Waves guided by a parallel plane perfectly conducting
structure.
6. b) A pair of perfectly conducting planes are separated by 8cm in air. For a frequency of 5GHZ with TM mode excited, determine the cut-off frequency and characteristic impedance.

Staring from 1st principles find the Electrical and Magnetic fields expressions for rectangular
Wave Guide operating in the TEmn mode.

7. Derive from 1st principles, the transverse field components for the TMmn mode. Hence find
the wave impedance for a rectangular WAVE GUIDE.

8 i) An air filled hollow rectangular Wave Guide has cross-sectional dimensions 12cm X 9cm. obtain
the cut off frequency for the subsequent modes:
TE10, TE20, TE01, TE11, and TE21.
ii) discuss why it is not possible to propagate a TEM wave inside a hollow Wave Guide of any cross section?

5.9. Deduce expression for propagation Constant, Wavelength and Velocity of propagation for TE waves ranging from parallel planes.
10.
6.Deduce expressions for cut-off wavelength, guide wavelength, phase constant and phase velocity in case of rectangular Wave Guide excited in TE mode.


U


NIT – V

PART – A

1. Compare: Wave Guide and Coaxial Transmission Lines.
2. Differentiate ranging from Transmission Lines and Wave Guides.
3. How is coaxial cable coupled to a Wave Guide?
4. Why is slot given in Wave Guide?
5. What is directional Coupler?
6. How do you suppress the unwanted modes?
7. What is the purpose of resonant obstacles in Wave Guides.?
8. State the function of directional Coupler?
9. What is the use of slots in a Wave Guide?
10. What are called unwanted modes in a Wave Guide?
11. Mention 2 applications of Wave Guide directional Couplers?
12. What is the purpose of mode filter?


PART – B

1. Explain in detail, the generation of various Wave Guide modes.
2. Discuss the operating principle of directional Coupler.
3.a) a) define the various modes of impedance matching in Wave Guides.
b) b) How do you suppress the unwanted modes? discuss.
4.3. Write a short notes on
4. a) Directional Coupler b) Resonant Obstacles in Wave Guide
5.
5.Discuss in detail the field distributions and SWR in Wave Guides.
6.
7.6. Explain the subsequent
i)i) Coupling and leakage through slots and holes in Wave Guide walls.
ii)ii) Reflected and Incident Waves and SWR in Wave Guide.
8.7. Write notes on
i) Waveguide directional couplers
ii) Currents in Wave Guide Walls
9.8. i) i) discuss how different modes can be excited in Wave Guides
ii) ii) explain in detail the impedance relations in Wave Guides

Earning:   Approval pending.