8436611 Anna University Microwave Question Papers

B.E./B.TECH.DEGREE EXAMINATION ,NOV/DEC 2005 VII -SEMESTER MICROWAVE ENGINEERING TIME :3 hrs MAX MARKS :100 PART -A (10 X 2 = 20 MARKS) 1. Write down the ABCD parameters of a lossless transmission line. 2. State the 'PHASE SHIFTING' property of S- parameters 3. Stae the two parameters that describe a directional coupler. Define them 4. Calculate the attenuation of a rotary vane attenuator if the angle of roatation is 34 degrees 5. What is TUNING with respect to microwave oscillators ? Name them 6. Drw the electronic admittance spiral of REFLEX KLYSTRON 7. Draw the equivalent circuits of pin diode under (a0 Reverse bias and (b) Forward bias 8. Which two phase angle make the voltage and current on A valanche transmit time device to be out of phase by 180 degrees? 9. Why is the SLOT located a the center of the SLOTTED SECTION? 10 What are LOW VSWR and HIGH VSWR and name the method followed to measure HIGH VSWR? PART -B (5 X 16 =80) 11 (i) Explain the method of measuring impedence at microwavr frequencies (ii) Give the relationship of LOADED and UNLOADED Q of a cavity 12 (a) (i) Obtain the relationship of S parameters in terms of ABCD parameters (ii) Find the S parameters of an ideal transformer of turns ratio 1:n OR (b) A certain two -port microwave junction can be represented by the following equivalent circuit. Determine the susceptance B and the turns ratio n of ideal transformer if the measurements give S11= -(1 + j )/3 +j ,S22 = 1-j/3 +j 13(a) (i) From the first principle ,derive the scatttering matrix of an ideal directional coupler. Hence or otherwise write down [s] matrix of HYBRID COUPLER and MAGIC - T (ii) What is the value of DIRECTIVITY of an ideal DIRECTIONAL COUPLER ? why? OR

(b) (i) An isolator, with a charecteristic impedence of 50 ohms has forward and reverse losses of 0.9 dB and 32 dB respectivily. Its input and output VSWR's are 1.09 and 1.16 respectivily when it is terminated by a 50 ohms load. Determine its S parameters. Assume zero phase components. (ii) Explain how the inductances and capacitances can be varied using IRESES and SCREWS (posts) 14 (a) Derive the expression for the gain of a TWT (b) Derive 'HULL CUT OFF' condition and 'HARTEE' condition of a cavity type mgnetron 15 (a) (i) Derive 'Manley Rowe Relations '. (ii) Use the above relations to find the poer gain of an UP CONVERTER and a DOWN CONVERTER OR (b) Write in detail the principle mechanism of operation and the application of IMPATT diode. -------------------------------------------------------------------------------------------------------------------------B.E./B.TECH.DEGREE EXAMINATION MAY/JUNE 2006 VII -SEMESTER MICROWAVE ENGINEERING TIME :3 hrs MAX MARKS :100 PART -A (10 X 2 = 20 MARKS) 1. Write down the transmissio parameters of an ideal transformer of turns ratio n:1 2. Express S11 of two port microwave component in terms of its equivalent ABCD parameters 3. For reciprocal two port microwave component the magnitude of scattering coefficient S11 is 0.091. Find its VSWR. 4. Obtain the coupling coefficient in dB of a directional coupler if the magnitude of its corresponding scattering parameter is 0.707. 5. What is C ring tuning with respect to Magnetron? 6. Write down two important difference between TWT and multi cavity klysron 7.Name two important materials that are used in Schottky -barrier diode. 8. Mention two basic difference between IMPATT and BARITT in terms of biasing and NOISE 9. Write down the bsic difference between 'Barretters' and 'Thermistors'. 10. Write down the relationship of uide wavelength ,cut off wavelength and free

space wavelength of a waveguide. PART -B (5 X 16 = 80) 11.(i) Name three different types of devices that are used to detect microwave piwer. (ii) What is the specific application of 'Double minma method' of microwave measurement? (iii) How do you measure the micowave frequency without frequncy meter? 12 (b) (i) Obtain the ABCD parameters of a series impedance Z ohms from the first priciple. (ii) An ideal transformer has 1000 turns on its primary and 100 turns on its secondry side. Assuming that it has a 50 ohms connectot on each side ,determine its scaterring parameters. 13 (a) (i) Is it possible to match all the oorts of alossless reciprocal microwave component ? Prove the same. (ii) The specification of a three port circulator are given as isolation = 30 dB , insertion loss = 2 , 5 dB and VSWR = 1.2. charecterize the circulator by its Sparameters. OR (b) (i) One wishes to realize a power divider with a power ratio of 2.5:1 between the two outputs. Determine the charecteristics impedence of the two output lines , with a 50 ohm input and evaluute all the terms of the scattering matrix (ii) Determine the scatering matrix of a crossing between two lines having charecteristic impedence of 50 ohms and 100 ohms 14 (a) (i) Draw any four types of SLOW WAVE STRUCTES used in TWT. (ii) Draw the electrical equivalent diagram of a cavity type magnetron (iii) What is ' strapping' with respect to magnetron? (iv) What are 'pushing' and 'pulling' with respect to magnetron? OR (b) A two cavity klystron operates at 4.5 GHz . The DC beam voltage is 10 KV, cavity gap spacing is 2 mm . For a given input, the magnitude of the gap voltage is 100 volts , the DC component Io = 3.6 A and the drift regeion l= 3 cm . Calculate (i) the item the electrons are in the gap 9ii0 the transit angle (iii ) the range of velocities of eletrons as they leave the gap reageion (iv) the maximum voltage gain. 15 (a) (i) Draw the equivalent circuit of schottky diode and write down its properties (ii) Draw the equivalent circuit of pin diode and show how it can be used as a TRANSMISSION TYPE SWITCHED LINE PHASE SHIFTER and as a SERIES SWITCH OR (b) (i) Pictorially represent the charecteristics (viz eletric field distribution ,the microwave voltage and the external current flow) of differnt regeions of the

IMPATT diode under reverse biased condition . Write down its typical charecteristics. (ii) Give the voltage current wavefrom with respect to time of a TRAPATT diode and write down its charecteristics (iii) Write down the advantages and limitations of PARAMETRIC AMPLIFIER -------------------------------------------------------------------------------------------------------------------------A 1201 B.E./B.Tech. DEGREE EXAMINATION, MAY/JUNE 2007. Seventh Semester Electronics and Communication Engineering EC 432 � MICROWAVE ENGINEERING Time : Three hours Maximum : 100 marks Answer ALL questions. V PART A �� (10 >< 2 : 20 marks) 1. Give the �K� band frequency range. 2. List the mode properties of a propagating waveguide. 3. Give the S �� matrix of H � plane Tee. 4. Define coupling co-efficient and directivity. I 5. What is the purpose of slow wave structures used in TWT? 6. Why Magnetron is called as crossed field device? 7. What is transferred electron effect? 8. State any two applications of parametric amplifier. 9. What is Bolometer? Give two examples. " 10. Name two methods to measure impedance. PART B'- (5 >< 16 : 80 marks) I 11. (a) Discuss the following properties of �S� matrix. (16) Y (i) Symmetry property (ii) Unitary property ` (iii) Phase shift property. , l Or (b) (i) What is scattering matrix? Derive scattering matrix formulation for �n� port network. _ (10) (ii) Relate Z,Y and ABCD parameters with �S� parameters. (6) 12. (a) (i) � Derive the �S� matrix for Magic Tee. (10) � (ii) Explain with diagrams Waveguide corners, bends and twists. (6) Or (b) (i) What is an isolator? Write down its �S� parameters. (4) (ii) From the first principle derive the scattering matrix parameters of a directional coupler. (12) 13. (a) (i) Draw a neat sketch showing ahelix type traveling wave tube and describe the mechanism of electron bunching. (11) (ii) How does a TWT differ from a Klystron amplifier? (3) (iii) How are the oscillations that are spontaneously generated in a TWT suppressed? (2) Or (b) (i) What is meant by velocity modulation? � (2) (ii) Explain the operation of a two cavity klystron amplifier. Derive

expressions for bunched beam current and efficiency. (14) 14. (a) Derive the Manley Rowe power relation. Show how it can be applied to find the gain of up converter and down converter. (16) Or (b) Write short notes on (i) GUNN Diode (8) (ii) IMPATT device _ (8) 15. (a) With neat block diagram explain how a Network Analyser can be used to measure the amplitude and phase of a signal over a wide frequency range. Also explain the measurement of reflection and transmission parameters and �S� parameters. (16) Or ' 2 A 1201 (b) Explain the following : - (i) Impedance measurement by reflectometer. (8) (ii) Measurement of �Q� by Reflectometer method. (8) -------------------------------------------------------------------------------------------------------------------------B.E./B.TECH.DEGREE EXAMINATION, NOV/DEC 2006 VII-SEMESTER MICROWAVE ENGINERING TIME : 3 HRS MAX MARKS : 100 PART - A (10 X 2 = 20 MARKS) 1. State the properties of Scattering matrix. 2. Define a reciprocal network. 3. What should be the minimum radius of curvature for E plane bend and H plane bend? Validate your answer. 4. When can you say that termination is matched to a system ? Give the structure of any such termination and state the significance of that structure 5. What are the slow wave structures ? Why and where are they used? 6. Can a Two Cavity Klystron Amplifier be used as an oscillator ? If yes ,how? 7. Define GUNN effect. 8. What is the necessary condition for an IMPATT diode to produce oscillations? 9. For what measurements would you use a slotted line carriage? 10 What are the measurement that can be performed using (a) spectrum analyser (b) Network analyser? PART -B (5 X 16 = 80 ) 11. Prove that it is not possible to construct a perfectly matched , lossless , reciprocal 3 port junction.

12 (a) (i) Expalin the working of a faraday rotation isolator (ii) Explain how power splitting occurs in (i) E plane tee (ii) H plane tee (iii) magic tee OR (b) (i) Define coupling factor and dirictivity of a directional coupler . Give significance of these terms. (ii) Explain the coupling mechanism in a Bethe -hole directional coupler and two hole directional coupler. 13 (a) (i) Describe the pie mode of oscillations in a magnetron (ii)Derive the hull cutoff voltage equation for a magnetron OR (b) Derive the manley -rowe power relation. 14 (a) With the help of energy band diagrams explain the working of a tunnel diode. OR (b) With mathematical substantiation expalin the velocity modulation and bunching process in a reflex klstron. 15 (a) (i) Discuss the classification of Bolometers (ii) Explain the frequency measurement technique using (i) slotted line (ii) resonant cavities (iii) Exaplin the double minima method of VSWR measurement OR (b) Explain the waveguide method for measuring the dieletric constant of a dieletric sample. -------------------------------------------------------------------------------------------------------------------------B.E. / B.Tech. DEGREE EXAMINATION, NOVEMBER/ DECEMBER 2007 Seventh semester (Regulation 2004) Electronics and Communication Engineering EC 1403 � MICROWAVE ENGINEERING (Common to B.E. part time) sixth Semester Regulation 2005) Answer all questions PART A � (10*2=20marks) 1. What are waveguides corners, bends and twists? 2. Give the X-band frequency range. 3. What are HEMT�s? 4. What is MESFET? 5. What is transferred electron effect? 6. What is the other name for O-type tubes? 7. Mention the basic materials required for microwave integrated circuit. 8. List the various types of strip lines used in MMIC. 9. Mention two methods to measure impedance. 10. Define return loss and write its expression.

PART B � (5*16=80) 11. (a) (i) What is a hybrids ring. With the help of a neat diagram explain its working principle. (ii) Derive scattering matrix of E-plane Tee using S-parameters theory. OR (b) (i) What are the advantages of S-parameters over �Z� or �Y� parameters. (ii) What is the directivity of an ideal directional coupler? Why. (iii) From the first principles derive the scattering matrix of an ideal directional coupler. 12. (a) (i) Explain the constructional details and operation of GaAs MESFET with neat diagrams and characteristics curves. OR (b) (i) What are avalanche transit time devices. (ii) With a neat diagram explain the construction and operating principle of IMPACT diode. (iii) Mention any two applications of IMPATT diode. 13. (a) (i) write down RWH theory of Gunn diode. (ii) Explain the various modes of operation of Gun diode. OR (b) (i) Describe with the neat sketch the constructional details and principle of operation of a reflex klystron tube. With the help of Applegate diagram illustrate the phenomenon of bunching. (ii) Derive expression for bunched beam current and efficiency. 14. (a) (i) Explain in detail with suitable diagrams the fabrication techniques of a monolithic microwave integrated circuit. OR (b) Explain in detail the various types of planar transmission lines with appropriate diagrams. 15. (a) Describe in detail with block diagram the measurement of VSWR through return loss measurement. OR (b) Explain in detail the measurement of load impedance through slotted line method. -------------------------------------------------------------------------------------------------------------------------B.E / B.Tech. DEGREE EXAMINATION,NOV/DEC 2007 MICROWAVE ENGINEERING VII SEMESTER Time : 3 Hrs Max Marks : 100 PART A (10 X 2 = 20 ) 1. What are waveguides corners ,bends and twists? 2. Give the X- band frequency range? 3. What are HEMT's? 4. What are MESFET ?

5. What is transferres electron effect? 6. hat is the other name for O-type tubes? 7. Mention the basic materials required for microwve integrated circuit. 8. List the various types of striplines used in MMIC. 9. Mention two methods to measure impedance. 10 Define return loss and write its expression PART - B ( 5 X 16 =80) 11 (a) (i) What is a hybrid ring ? With the help of a neat diagram explain its working principle. (ii) Derive scattering matricx of E- plane Tee using S- parametre theory (OR) (b) (i) What are the advantages of S-parameters over 'Z' or 'Y' parameters. (ii) What is the directivity of an ideal directional coupler ? Why? (iii) From the first principles derive the scattwering matrix of an ideal directional coupler? 12 (a) Explain the constructional details and priciples of operations of GaAs MESFET with neat diagrams and charecteristic curves. OR (b) (i) What are avalanche transit time devices? (ii) With neat diagrams explain the construction and operating priciple of IMPATT diode. (iii) Mention any two applications of IMPATT diode. 13(a) (i) Write down RWH theory of gunn diode (ii) Explain the various modes of operation of Gunn diode OR (b) (i) Describe with the neat sketch the constructional details and principles of operation of a Reflex Klystron tube .With the help of Applegate diagram illustrate the phenomenon of bunching. (ii) Derive expressions for bunched beam current and efficiency. 14 (a) Explain in detail with suitable diagrams the fabrication techniques of a monolithic microwave integrated circuit. OR (b) Explain in detail the various types of planer transmission lines with appropriate diagrams.

15 (a) Describe in detail with block diagram the measurement of VSWR through return loss measurements. OR (b) Explain in detail the measurements oF load impedeance through slotted line method. --------------------------------------------------------------------------------------------------------------------------