RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY Kirumampakkam,Puducherry DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

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RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY Kirumampakkam,Puducherry-607402 DEPARTMENT OF ELECTRONICS AND

1 RAJIV GANDHI COLLEGE OF ENGINEERING AND TECHNOLOGY Kirumampakkam,Puducherry DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK FOR EC T55 - TRANSMISSION LINES AND WAVEGUIDES G.LAXMINARAYANAN, AP/ECE RGCET

2 EC T55 - TRANSMISSION LINES AND WAVEGUIDES COURSE OBJECTIVE To introduce the various types of transmission lines and to discuss the losses associated. To give thorough understanding about impedance transformation and matching. To use the Smith chart in problem solving. UNIT- I Network Parameters: Open circuit impedance (Z) parameters - short circuit admittance (Y) parameters - transmission (ABCD) parameters and inverse transmission parameters - Hybrid (h) parameters and inverse hybrid parameters - Conversion between parameters Design of K type and m-derived filters Switched twin T network, attenuators and equalizers. UNIT- II Transmission Line Theory: Transmission line equation Primary and secondary constants - Infinite line- attenuation and phase constants- skin effect- wavelength- velocity of propagation- group velocity. Waveform distortion- distortion less transmission line-telephone cable- inductance loading of telephone cables. Open and short circuit lines. UNIT-III Transmission Line at Radio Frequencies: Line with any termination- Input impedance, input impedance of a lossless line, Reflection coefficient- Standing wave ratio. Ultra high frequency lines- Characteristics impedance, SWR, Smith chart- applications of smith chart- Quarter wave transformer- Stub matching- Single and double. UNIT IV Guided Waves and Rectangular waveguides:introduction - Waves between parallel planes - Transverse electric waves,transverse magnetic waves, Transverse electromagnetic waves and their characteristics -Wave impedances. Rectangular waveguides - TE and TM waves in rectangular waveguide- Dominant mode - Impossibility of TEM waves in wave guides - Wave impedance and characteristic impedance - Excitation methods for various modes. UNIT V Circular Wave Guides: Introduction TE and TM waves in circular waveguide- Wave impedance - Attenuation factor and Q of wave guides- Wave impedance- Excitation mode sin circular wave guides. Microwave resonators introduction Coaxial resonator-waveguide, rectangular and circular cavity resonator - Cavity excitation and tuning Qfactor of micro wave cavities (Qualitative treatment only). Text Books: 1. John. D. Ryder, Network lines and fields, PHI Learning, Second Edition, Edward C. Jordan and Keith G. Balaman, Electromagnetic waves and radiating systems, Second Edition, PHI Learning, P. Dananjayan, Transmission Lines And Wave Guides Lakshmi Publications, Chennai, 2012 Reference Books: 1. M.E. Van Valkenburg, Network Analysis, PHI, Third Edition, William H Hayt and Jr John A Buck, Engineering Electromagnetics Tata Mc Graw-Hill Publishing Company Ltd, New Delhi, David K Cheng, Field and Wave Electromagnetics, Pearson Education Inc, Delhi, John D Kraus and Daniel A Fleisch, Electromagnetics with Applications, Mc Graw Hill Book Co, 2005 Web references:1. Transmission Line Parameter Calculator 2. SPICE Simulation of Transmission Lines

3 DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK Transmission Lines and Waveguides UNIT I PART A (2 MARKS) 1. What are the open circuit impedance parameters( NOV 2015/TLW) 2. Distinguish between attenuators and equalizers. ( NOV 2015/TLW) 3. Draw the equivalent circuit of two port network using transmission parameters. ( NOV 2015/NTL) 4. Write the condition for two port network to be reciprocal. ( NOV 2015/NTL) 5. Determine the cut off frequency for T type the low pass filter, whose L/2 =40mH and C=0.5µF. ( NOV 2015/NTL) 6. Give the expression for the characteristic impedance of symmetrical T and π networks. ( NOV 2015/NTL) 7. Define two port network. (NOV 2013 NTL) 8. Draw the hybrid parameter model for two port network. (NOV 2013 NTL) 9. What is m derived filters (NOV 2013 NTL) 10. What are equaliozers. (NOV 2013 NTL) 11. Define characteristic impedance. (NOV 2013 NTL) 12. Give the expression for ABCD parameters.(nov 2016) 13. What are the significances of Attenuators?(NOV 2016) PART B (11 Marks) 1. A.Prove that for a passive bilateral network the ABCD parameter has the relationship of AD- BC=1. b. the parameters of a two port network are Z 11 =10 ohms, Z 22 =20 ohms, Z 12 =Z 21 =5 ohms. Find the ABCD parameter and equivalent T network. ( NOV 2015/TLW) 2. a.draw the π section of a constant low pass k filter and derive the equation for cut off frequency. b. design a m derived high pass filter with a cut off frequency of 10 khz design impedance of 500 ohms and m=0.4. ( NOV 2015/TLW) 3. Compute the Z parameter for T type two port network whose series arm is 1 ohms and 2 ohm, shunt armis 2 ohms and load is 4 ohms. ( NOV 2015/NTL) 4. Explain in detail about the series and parallel connection of two port network with respect to impedance and admittance parameter. ( NOV 2015/NTL) 5. design a constant K low pass filter having cutoff frequency of 2.5 Khz and design resistance of Also find the frequency at which this filter produces attenuation of

4 db. Find the characteristic impedance and phase constant at pass band. ( NOV 2015/NTL) 7. Explain the salient features of Twin T and bridged T attenuator with their design equations. ( NOV 2015/NTL) 8. Write short notes on h parameter and ABCD parameters. (NOV 2013 NTL) 9. Explain in detail about the interconnection of two port network. (NOV 2013 NTL) 10. Write short notes on attenuators and equalizers. (NOV 2013 NTL) 11. Draw twin Twin T and bridged T network and explain them briefly 12. (a) Derive the design equation of a m derived high pass filter along with the plot of impedance variation. (NOV 2016) (b) Explain Y parameter in terms of h parameters. (NOV 2016) 12. (a) Explain the variation of characteristic impedance of a low pass constant K filter as a function of frequency. (NOV 2016) (b) Explain about the need of hybrid parameters and inverse transmission parameters. (NOV 2016) UNIT II 2 MARKS 1. What is skin effect? (APRIL 2015)(NTL) (NOV/DEC 2014)(EW&WG) (NOV 2013)(NTL) 2. What is an infinite line? (NOV/DEC 2014)(NTL) 3. What is the relation among phase, group and free space velocities? (NOV/DEC 2014)(NTL) 4. Relate group velocity and phase velocity. (NOV/DEC 2014)(NTL) 5. Mention the types of line distortion. (NOV 2013)(NTL) 6. What is a distortion less line? What is the condition for distortion less line? (NOV 2013)(NTL) 7. Define velocity of propagation and write its unit. (NOV 2015)(TLW) 8. What is meant by continuous loading in telephone cable? (NOV 2015)(TLW) 9. State the properties of infinite line. (NOV 2016) 10. What is the need of loading a telephone cables? (NOV 2016) PART B 1. Derive standard transmission line equation. (APRIL 2015)(NTL) (NOV/DEC 2014)(NTL) 2. Derive the expression for cut-off frequency, phase constant and phase velocity of wave in a circular waveguide. (NOV/DEC 2014)(EW&WG) 3. Explain in detail about the waveform distortion. (NOV 2013)(NTL) 4. What are the types of inductance loading in telephone cables? Explain. (NOV 2013)(NTL) 5. A pair of parallel perfectly conducting plates is separated by 7 cm in air and carries a signal with frequency of 6 GHz in TE 1 mode. Find the cutoff frequency and cut of wavelength, attenuation and phase constant. (NOV 2013)(NTL) 6. Derive the expression for general solution of transmission line equation.(nov 2015/NTL) 7. Develop the condition to be satisfied for a distortion less line. (NOV 2015/NTL) 8. Define the primary constants of transmission line and obtain the characteristic impedance and propagation constant interms of primary constants. (NOV 2015)(TLW) 9. Explain the various types of waveform distortions in transmission line and obtain the condition for distortion less lines. (NOV 2015)(TLW

5 10. Discuss the two types of waveform distortion on a transmission line and obtain the condition for distortion less line(nov 2016). 11. (a). Derive attenuation and phase constants of a transmission line. (NOV 2016) (b). Mention the importance of group velocity in transmission line. (NOV 2016) UNIT III 2 MARKS 1. Distinguish between TE and TM waves in guided wave. (APRIL 2015)(AWP) 2. What is the need of quarter wave transformer? (Nov/Dec 2014)(NTL) 3. What are the types of stub tuners.? (Nov/Dec 2014)(NTL) 4. Define SWR. ( NOV 2015/TLW) 5. List the application of Smith chart. ( NOV 2015/TLW) 6. Define reflection co efficient. (NOV 2013 NTL) 7. Define Standing wave ratio. (NOV 2016) 8. Design a quarter wave transformer to match load of 200 ohms to a source resistance of 500 ohms. The operating frequency is 200 MHz. (NOV 2016) PART B 1. Explain in detail about smith chart and its uses. (APRIL 2015)(NTL) 2. Differentiate quarter wave transformer from half wave transformer. Derive Z m for quarter wave transformer. (APRIL 2015)(NTL) 3. Explain the principle of single and double stub tuners with neat diagram. (Nov/Dec 2014)(NTL) 4. Explain in detail about the applications of smith chart and single stub matching. ( Nov 2013 NTL) 5. A lossless transmission line in air has a characteristic impedance of 300 ohms and is terminated by unknown impedance. When the frequency is 200 MHz, the SWR is 4.48 and first voltage minima are situated at 6 cm from the load. Determine the complex reflection co-efficient and terminating impedance of the line. ( Nov 2015/TLW) 6. Explain single stub matching on a transmission line and derive the expression for location and the length of the stub used for matching on a line. ( Nov 2015/TLW) 7. Derive an expression for SWR.(Nov 2013/NTL) 8. Explain single stub matching on a transmission line and drive the expression for location and length of stub used for matching on a line. (NOV 2016) 9. (a) Using double stub matching, match a complex load of ZR = j ohms to a line with characteristics resistance R0 = 75 ohms. Determine the stub lengths, assuming a quarter wavelength spacing are maintained between two short circuited stub. (NOV 2016) (b)briefly explain the applications of Smith chart. (NOV 2016)

6 UNIT IV 2 MARKS 1. Define TEM. (APRIL 2015 EW &WG) 2. List out the power losses in a rectangular wave guide. (APRIL 2015 EW &WG) 3. Define dominant mode. (APRIL 2015 EW &WG) 4. Give any two TEM modes in a losses of circular waveguide. (APRIL 2015 EW &WG) 5. What is power loss in circular waveguide. (APRIL 2015 EW &WG) 6. List the characteristics of TEM wave. (Nov/Dec 2014)(wawp) 7. Define wave impedance and write the expression for TE, TM wave in guided wav es. (Nov/Dec 2014)( EW&WG) 8. What dominant mode of TE and TM waves in circular wave guide. (Nov/Dec 2014)( EW&WG) 9. What are dominant mode and de genearate mode in rectangular wave guide. (Nov/Dec 2014)( EW&WG) 10. What are de genearate mode. Nov 2013 (EW &WG) 11. Give any two TEM modes in losses of circular waveguides. Nov 2013 (EW &WG) 12. Write notes on transverse electrical waves.(april 2014/WAWP) 13. Define wave impedance. (April 2014/WAWP) ( NOV 2015/TLW) 14. State the characteristics of TEM waves. (April 2014/WAWP) 15. Give the quation for the propagation constant and wavelength for TEM waves between parallel plates.( Nov 2015/WAWP) 16. TEM waves is not possible through hollow rectangular waveguides.justify. ( NOV 2015/TLW) 17. What is dominant mode of TE and TM waves in circular waveguide. ( NOV 2015/TLW) 18. Why TEM mode is not possible in waveguides? (NOV 2016) 19. What is wave impedance. (NOV 2016) PART B 1. Discuss the transmission of TE waves in a guided wave between parallel perfectlyconducting planes with necessary expressions and diagrams for the field components.(11) (APRIL 2015)(AWP) 2. Briefly explain the wave propagation of TM waves in a rectangular waveguide withrelevant expressions for the field components.(11) (APRIL 2015)(AWP) 3. Explain the characteristics of TE, TM and TEM waves of guided waves. (APRIL 2015 EW &WG) 4. Explain the TE and TM waves in rectangular waveguide. (APRIL 2015 EW &WG) 5. Briefly explain the rectangular waveguide. (APRIL 2015 EW &WG) 6. Write in detail about wave impedance and excitation modes in circular waveguides. (APRIL 2015 EW &WG) 7. Explain TE wave transmission parallel plates perfectly conducting planes with necessary expression. (Nov/Dec 2014)( WAP) 8. Discuss TM wave propagation in rectangular wavguides. (Nov/Dec 2014)(WAP) Derive the expression for field strength for TE waves between parallel plates propagating in z direction.(nov/dec 2014)( EW&WG) 9. Derive the expression for wave impedance of TE, TM and TEM waves between a pair of perfectly conducting planes. (Nov/Dec 2014)( EW&WG) 10. Explain about excitation mode in rectangular wavguides. (Nov/Dec 2014)( EW&WG) 11. Explain the dominant modes and wave impedance of rectangular wavguides. Nov 2013 (EW &WG)

7 12. Explain the excitation modes of various modes of rectangular waveguides Nov 2013 (EW &WG) 13. Explain the characteristics of Transverse electromagnetic waves. (April 2014/WAWP) 14. Describe with relevant equation about the rectangular waveguides. (April 2014/WAWP) 15. Derive the field configuration,cut off frequency and velocity of propagation for TM waves in rectangular waveguide. (April 2014/EW&WG) 16. a) TM waves cannot exist in single conductor waveguide, justify the statement using maxwells equation. b) An X-band air filled rectangular waveguide has inner dimension of a=2.3 cm and b=1 cm. Calculate The cutoff frequency in the following modes, TE 10,TE 20,TM 11,TM 12 also check which of the mode will propagate along tile waveguide when the signal frequency is 10 GHz. 17. Describe the propagation of TE waves in rectangular waveguide. (Nov 2015/WAWP) 18. Explain in detail about excitation modes in rectangular waveguides. ( Nov 2015/WAWP) 19. Derive the electromagnetic field expression for the transverse magnetic waveguides in a parallel plane perfectly conducting structure, list the characteristics of TM waves. ( Nov 2015/TLW) 20. A rectangular air filled copper waveguide with dimension of cm X cm cross section and 30 cm length is operated at 9.5 GHz with dominant mode. Find cut off frequency, guide wave length, phase velocity and characteristic impedance. ( Nov 2015/TLW) 21. Derive the attenuation constant due to losses in walls of rectangular guide for dominant mode. (NOV 2016) 22. Explain about the characteristics of TE and TM waves between parallel planes and derive the expression for the field strength. (NOV 2016) UNIT V 2 MARKS 1. Give the applications of cavity resonators. (APRIL 2015)(AWP) 2. Define Q factor of a cavity resonator. (APRIL 2015 EW &WG) 3. State the need of an attenuator and define attenuation factor. (Nov/Dec 2014)(WAWP) 4. Write the application of circular wave guide. (Nov/Dec 2014)( EW&WG) 5. What is cavity resonator. (Nov/Dec 2014)( EW&WG) 6. Why rectangular and circular cavities can be used as microwave resonators. (Nov/Dec 2014)( EW&WG) 7. Define unloaded Q o of cavity resonator. Nov 2013 (EW &WG) 8. List the excitation modes in circular waveguides. (April 2014/WAWP) 9. Write a short notes cavity excitation. (April 2014/WAWP) 10. List the excitation modes in rectangular waveguides. (April 2014/WAWP) 11. Define cavity resonator and give its applications. ( Nov 2015/WAWP) 12. What are the advantages of circular waveguides. ( Nov 2015/WAWP) 13. Define Q factor of a microwave cavity. ( Nov 2015/TLW) 14. Define unloaded and loaded Q of microwave resonator. (NOV 2016) 15. Write the expression for resonant frequency for TE and TM mode in circular cavity resonator. (NOV 2016)

8 PART B 1. Derive and explain the wave impedance of circular waveguide.(6) (APRIL 2015)(AWP) 2. Write short notes on excitation modes in circular waveguide.(5) (APRIL 2015)(AWP) 3. Explain in detail about rectangular and circular cavity resonators.(11) (APRIL 2015)(AWP) 4. Explain the rectangular cavity resonator. (APRIL 2015 EW &WG) 5. Discuss about the coaxial resonator. (APRIL 2015 EW &WG) 6. Derive the Q factor of a rectangular cavity resonator in TE mode. (Nov/Dec 2014)(WAP) 7. What is meant by cavity resonator. Derive the expression for resonant frequency of rectangular cavity resonator. (Nov/Dec 2014)( EW&WG) 8. Explain the attenuation factor and Q of wave guides. Nov 2013 (EW &WG) 9. Explain in detail of TE and TM waves in circular wave guides. Nov 2013 (EW &WG) 10. Explain circular cavity resonator. Nov 2013 (EW &WG) 11. Write short notes on a. Q factor of microwave cavities b. cavity excitation and tuning. Nov 2013 (EW &WG) 12. Describe in detail about microwave resonators. (April 2014/WAWP) 13. Explain in detail about rectangular and circular cavity generator. (April 2014/WAWP) 14. Describe the principle and operation of circular cavity resonator. ( Nov 2015/WAWP) 15. A circular waveguide is used for a signal at a frequency of 11GHz propagated in TE 01 mode having internal diameter of 4.5 cm. Calculate the cutoff wavelength, guide wave length, group velocity, phase velocity and characteristic impedance. 16. Explain with neat diagram, how a circular cylindrical cavity is excited in TM 010 mode by a rectangular waveguide operating in dominant mode. How such cavity is tuned. ( Nov 2015/TLW) 17. Derive the field component of TM waves in rectangular cavity resonator. (NOV 2016) 18. (a) A circular wave guide has a internal diameter of 4 cm. For a 10 GHz signal propagated in it in the TE11 mode, calculate cut-off wavelength, guide wavelength and characteristics wave impedance. (NOV 2016) (b) Brief about excitation mode in circular waveguide. (NOV 2016)

EC6503 Transmission Lines and WaveguidesV Semester Question Bank

EC6503 Transmission Lines and WaveguidesV Semester Question Bank UNIT I TRANSMISSION LINE THEORY A line of cascaded T sections & Transmission lines General Solution, Physicasignificance of the equations 1. Derive the two useful forms of equations for voltage and current