valliammai engineering college semester/ec6701-rf and... · ec 6701 rf and microwave engineering...

EC 6701 RF and Microwave Engineering

VALLIAMMAI ENGINEERING COLLEGE SRM Nagar, Kattankulathur – 603 203.

DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING

EC6701 – RF & MICROWAVE ENGINEERING

QUESTION BANK

IV- YEAR VII SEM

ACDEMIC YEAR: 2017-2018 ODD SEMESTER

Prepared by

1. K. SOBANA, AP ECE

2. D.MURUGESAN, AP ECE

3. R.BIRUNDHA, AP ECE


UNIT I: TWO PORT NETWORK THEORY

Review of Low frequency parameters: Impedance, Admittance, Hybrid and ABCD parameters,

Different types of interconnection of Two port networks, High Frequency parameters, Formulation of S

parameters, Properties of S parameters, Reciprocal and lossless Network, Transmission matrix, RF

behavior of Resistors, Capacitors and Inductors.

PART A

Q. No Questions BT Level Domain

1. Name the Low Frequency parameters. BTL 1 Remembering

2. What is the need for S-parameters?

BTL 1 Remembering

3. Draw the equivalent circuit of a practical capacitor and

inductor.

BTL 1 Remembering

4. Give the application of Thin-film chip resistors.

BTL 1 Remembering

5. List the properties of S- parameters.

BTL 1 Remembering

6. Write the equation for VSWR at port 1 in terms of S11.

BTL 1 Remembering

7. Describe Reflection Co-efficient at the input side and output

side of a two-port network in terms of S-parameters.

BTL 2 Understanding

8. A 5dB attenuator is specified as having VSWR of 1.2.

Assuming the device is reciprocal, find the S-parameters.

BTL 2 Understanding

9. Draw the electric equivalent circuit for a high frequency

inductor. BTL 2 Understanding

10. Discuss the advantages of scattering parameters?

BTL 2 Understanding

11. Demonstrate reciprocal and symmetrical networks.

BTL 3 Applying

12. Mention the limitations in measuring Z, Y and ABCD

parameter at microwave frequencies.

BTL 3 Applying

13. Show the principal advantage of microwave frequencies over

lower frequency.

BTL 3 Applying

14. Infer lossless network.

BTL 4 Analyzing

15. Explain insertion loss?

BTL 4 Analyzing

16. Analyze transmission loss in terms of S-parameters?

BTL 4 Analyzing

17. How would you explain return loss of a two-port network?

BTL 5 Evaluating

18. Explain reflection loss?

BTL 5 Evaluating

19. Discuss four applications of RF.

BTL 6 Creating


20. Can you explain the transmission matrix and its advantages?

BTL 6 Creating

PART B

1. (i)Describe the properties and applications of RF waves. (8)

(ii)Examine in detail about low frequency parameters. (8)

BTL 1 Remembering

2. (i)Show Z and Y matrix formulation of multiport network.(8)

(ii)Tell the limitations of ABCD,Z,Y and h parameters. (8)

BTL 1 Remembering

3. (i)Define ABCD matrix of a two port network and obtain ABCD

matrix for series impedance and shunt admittance. (8)

(ii)Compute ABCD matrix for a T network and Pi network. (8)

BTL 1 Remembering

4. Draw the High Frequency equivalent of wire, resistors, inductors

& capacitors and Explain. (16)

BTL 1 Remembering

5. (i)Summarize the need for S-parameters and define S-parameters

for a two port network. (8)

(ii) Write the expression of losses in terms of S parameters. (8)

BTL 2 Understanding

6. (i)Interpret S Matrix for N port network. (8)

(ii)State and verify the symmetry property of the reciprocal

networks. (8)

BTL 2 Understanding

7. Discuss and explain the zero, unitary and phase shift property of S

parameters. (16)

BTL 2 Understanding

8. (i)Formulate the S parameter of a two port network with

mismatched load. (8)

(ii)Explain the scattering matrix for lossless junction. (8)

BTL 3 Applying

9. Demonstrate transmission matrix for a cascade connection of two

port networks? Explain them and obtain the relationship with S

Matrix. (16)

BTL 3 Applying

10. The S parameters of a two port network are given by S11=0.2

90°, S22= 0.2 90°, S12=0.5 90°& S21=0.5 0°

(i)Analyze whether the network is lossy or not? Is the network

symmetrical and reciprocal? (8)

(ii)Find the insertion loss of the network, What is return loss at

port 1 when other ports are matched terminated. (8)

BTL 4 Analyzing

11. (i)Obtain the Z-parameters of the two-port T- network shown in

figure. (8)

(ii)A reciprocal device has VSWR=1.5 and insertion loss of 2dB.

BTL 4 Analyzing


Find S parameter. (8)

12. The S parameters of a two port network are given by S11=0.2 0°,

S22= 0.1 0°, S12=0.6 90°& S21=0.6 90°

(i)Examine that the network is reciprocal but not lossless. (8)

(ii)Find the return loss at port1 when port 2 is short circuited. (8)

BTL 4 Analyzing

13. A shunt impedance Z is connected across a transmission line with

characteristic impedance Z0. Determine the S matrix of the

junction.

(16)

BTL 5 Evaluating

14. Two transmission lines of characteristic impedance Z1 and Z2 are

joined at plane PP’. Develop S parameters in terms of

impedances. (16)

BTL 6 Creating

UNIT II RF AMPLIFIERS AND MATCHING NETWORKS

Characteristics of Amplifiers, Amplifier power relations, Stability considerations, Stabilization Methods,

Noise Figure, Constant VSWR, Broadband, High power and Multistage Amplifiers, Impedance matching

using discrete components, Two component matching Networks, Frequency response and quality factor, T

and Pi Matching Networks, Microstrip Line Matching Networks.

PART A

Q. No Questions BT

Level

Domain

1. What are the components required for impedance matching at

low, mid and high frequencies.

BTL 1 Remembering

2. Define forward current gain and reverse voltage gain

BTL 1 Remembering

3. List are the considerations in selecting the matching network?

BTL 1 Remembering

4. Name two noise parameters. BTL 1 Remembering

5. Show the purpose of a matching network and smith chart? BTL 1 Remembering

6. Tell the main drawback of a single stub matching network? BTL 1 Remembering

7. Summarize the basic steps in the design process of RF

amplifier circuits?

BTL 2 Understanding

8. Describe power gain of amplifier in terms of S-parameters and

reflection coefficient.

BTL 2 Understanding


9. Draw the diagram for stabilization of input port through series

resistance and shunt conductance.

BTL 2 Understanding

10. Discuss the four adjustable parameters for matching networks. BTL 2 Understanding

11. Express the noise figure of a two port amplifier. BTL 3 Applying

12. Show the difference between conditional and unconditional

stabilities of amplifier

BTL 3 Applying

13. Examine why impedance matching is required. What are the

other constrains required.

BTL 3 Applying

14. Analyze the parameters used to evaluate the performance w0f

an amplifier?

BTL 4 Analyzing

15. Infer on feedback of RF circuit. BTL 4 Analyzing

16. Explain unilateral power gain and Noise Figure BTL 4 Analyzing

17. How will you write the function of matching networks BTL 5 Evaluating

18. Estimate the expression for nodal quality factor with loaded

quality factor.

BTL 5 Evaluating

19. Draw typical output stability circle and input stability circle BTL 6 Creating

20. Can you explain transducer power gain? BTL 6 Creating

PART B

1. Describe the characteristics of amplifier and Derive transducer

power gain, unilateral power gain, available power gain and

operating power gain of a microwave amplifier using S

parameters. (16)

BTL 1 Remembering

2. Explain the smith chart approach to design the L-section and

T-section matching Networks. (16)

BTL 1 Remembering

3. (i)Examine the expression for input stability circle equation

and output stability equation. (16)

BTL 1 Remembering

4. (i)List and explain stabilization Methods with configuration at

input and output port. (8)

(ii)Explain unilateral design for gain in detail and derive the

frequency dependent unilateral figure of merit equation. (8)

BTL 1 Remembering

5. (i)Summarize on Constant VSWR circles. (8)

(ii)Explain unconditional stability and the tests to conclude the

same. (8)

BTL 2 Understanding


6. How would you explain the following

(i) Pi section matching Networks. (8)

(ii) Microstripline Matching Networks. (8)

BTL 2 Understanding

7. (i)Examine single stub matching network. (8)

(ii)Draw the double stub matching network and explain it in

detail. (8)

BTL 2 Understanding

8. (i) (i)Show general noise figure and NF circles. (8)

(ii)Also show that the noise figure of a cascaded multistage

amplifier is F=F1+ (F2-1)/GA1+ (F3-1)/GA2+….. Where F1 and

F2…. are noise figures and GA1 and GA2…are power gains. (8)

BTL 3 Applying

9. (i)Demonstrate on broad band, high power and multistage

amplifiers. (8)

(ii)Design LC network to match source impedance

Zs=50+j25Ω to the load ZL=25-j50Ω.Assume Zo=50Ω;

f=2GHz. Use smith chart. (8)

BTL 3 Applying

10. 1. (i)Summarize on matching network? Why is this required?

2. (8)

(ii)Design a lumped element ‘LC’ network for matching

ZL=10+j10Ω to a 50Ω transmission line at 1 GHz. (8)

BTL 4 Analyzing

11. The S-parameters for a transistor is given below. Determine

its stability and draw the input and output stability circles, use

smith chart. S11=0.385∟-53°, S12=0.045∟90°, S12=2.7∟78°

and S22=0.89∟-26.5°. (16)

BTL 4 Analyzing

12. A MESFET operated at 5.7GHz ha the following S

parameters: S11=0.5∟-60°, S12=0.02∟0°, S21=6.5∟115° and

S22=0.6∟-35°. Determine if the circuit is unconditionally

stable and Find the maximum power gain under optimal

choice of reflection coefficients, assuming unilateral design

(S12=0). (16)

BTL 4 Analyzing

13. An RF amplifier has the following S parameters: S11=0.3∟-

70°, S21=3.5∟85°, S12=0.2∟85°, S22=0.4∟-10°. Further

Vs=5V∟0°, Zs=40Ω and ZL=73Ω. Assuming Zo=50Ω. Find

GT, GTU, GA and G. Also find Power delivered to the load PL,

available power from source PA and incident power to

amplifier Pinc. (16)

BTL 5 Evaluating

14. Draw the 8dB gain circle of the transistor with the following S

parameters at 1GHz. S11=0.46∟-97°, S12=0.06∟-22°,

S21=7.1∟112° and S22= 0.57 ∟-48°. (16)

BTL 6 Creating


UNIT III PASSIVE AND ACTIVE MICROWAVE DEVICES

Terminations, Attenuators, Phase shifters, Directional couplers, Hybrid Junctions, Power dividers,

Circulator, Isolator, Impedance matching devices: Tuning screw, Stub and quarter wave transformers.

Crystal and Schottky diode detector and mixers, PIN diode switch, Gunn diode oscillator, IMPATT diode

oscillator and amplifier, Varactor diode, Introduction to MIC.

PART A

Q.No Questions BT

Level

Domain

1. Give the significance of Rat- race junctions.

BTL 1 Remembering

2. Identify the use of matched termination.

BTL 1 Remembering

3. Define Directivity and coupling factor of Directional coupler.

BTL 1 Remembering

4. Tell about matched terminators?

BTL 1 Remembering

5. What are waveguide corners, bends and twists?

BTL 1 Remembering

6. List the basic parameters to measure the performance of a

Directional Coupler?

BTL 1 Remembering

7. Summarize sum and difference arm BTL 2 Understanding

8. Differentiate between gyrator and phase changer? BTL 2 Understanding

9. Discuss how isolator is designed using 3 port circulator BTL 2 Understanding

10. Describe Faraday’s rotation? BTL 2 Understanding

11. Demonstrate Gunn diode and list the modes. BTL 3 Applying

12. Illustrate Negative resistance in Gunn diode? BTL 3 Applying

13. Show what is step recovery diode? BTL 3 Applying

14. Infer the factors reducing the efficiency of IMPATT diode? BTL 4 Analyzing

15. Explain the main advantage of TRAPATT over IMPATT? BTL 4 Analyzing

16. Classify the fabrication techniques in MMIC BTL 4 Analyzing

17. Analyze the acronyms IMPATT, TRAPATT and BARITT. BTL 5 Evaluating


18. Determine the substrate materials used in MMICs?

BTL 5 Evaluating

19. Elaborate on the applications of TRAPATT diode? BTL 6 Creating

20. Discuss the various types of strip lines used in MMIC. BTL 6 Creating

PART B

1. With neat diagram explain the operation of attenuator and phase

shifter in detail. (16)

BTL 1 Remembering

2. Show the operation and properties of E-plane Tee and H-plane

Tee. Derive their S parameters. (16)

BTL 1 Remembering

3. (i)Find scattering matrix for Hybrid Tee/Magic Tee using S

parameter theory. (8)

(ii)List and explain the applications of magic Tee. (8)

BTL 1 Remembering

4. (i)Write notes on Hybrid ring/Rat race junction. With the help of a

neat diagram explain its working principle. (8)

(ii)Show with neat diagram waveguide terminations, corners, twists

and bends. (8)

BTL 1 Remembering

5. (i)From the first principles derive the Scattering matrix of a multi

hole Directional Coupler. (8)

(ii)Infer the characteristics of directional coupler in terms of S

parameters and explain in detail two hole directional coupler. (8)

BTL 2 Understanding

6. Demonstrate the principle of microwave transmission through

ferrite and explain how a Gyrator and isolator is designed based

on this effect. (16)

BTL 2 Understanding

7. (i)Explain principle of operation of 3 port circulator with S

parameter. (8)

(ii)Construct four Port circulator using Magic Tee and also by

using Directional Coupler. (8)

BTL 2 Understanding

8. With neat diagrams, explain the operation of Tunnel diode and its

application as an oscillator and amplifier. (16)

BTL 3 Applying

9. (i)How would you explain varactor diode and its application as

frequency multiplier? (10)

(ii) Explain in detail about step recovery diode. (6)

BTL 3 Applying

10. (i)Examine crystal diode, schottky diode, diode detector and

diode mixer circuit. (8)

(ii)Explain in detail PIN diode and its applications. (8)

BTL 4 Analyzing


11. Discuss the working principle of Gunn diode as a transferred

electron device with two valley model, Also draw the structure,

equivalent circuit and V-I characteristics of Gunn diode. (16)

BTL 4 Analyzing

12. Describe the domain formation in Gunn diode with various modes

of operations. Also explain Gunn diode oscillator (16)

BTL 4 Analyzing

13. (i)What are avalanche transit time devices? Explain the operation

and construction of IMPATT diode. (8)

(ii)Explain mechanism of oscillation of IMPATT and as power

amplifier. (8)

BTL 5 Evaluating

14. Can you explain the materials used for MMIC fabrication? Also

explain with neat diagrams the fabrication process of MMICs.(16)

BTL 6 Creating

UNIT IV MICROWAVE GENERATION

Review of conventional vacuum Triodes, Tetrodes and Pentodes, High frequency effects in vacuum Tubes,

Theory and application of Two cavity Klystron Amplifier, Reflex Klystron oscillator, Traveling wave tube

amplifier, and Magnetron oscillator using Cylindrical, Linear, Coaxial Voltage tunable Magnetrons,

Backward wave Crossed field amplifier and oscillator.

PART A

Q.No Questions BT Level Domain

1. What is velocity modulation? BTL 1 Remembering

2. State the transferred electron effect. BTL 1 Remembering

3. Tell about Cross field tubes? BTL 1 Remembering

4. Define density modulation? BTL 1 Remembering

5. Quote the difference between TWTA and Klystron Amplifier. BTL 1 Remembering

6. List the advantages of Parametric amplifier BTL 1 Remembering

7. Summarize the applications of reflex klystron? BTL 2 Understanding

8. Describe the condition for oscillation in Reflex Klystron? BTL 2 Understanding

9. Discuss any four high frequency limitations. BTL 2 Understanding

10. Give the drawbacks of klystron amplifiers. BTL 2 Understanding

11. Demonstrate frequency pulling and frequency pushing in

magnetrons?

BTL 3 Applying


12. Examine the effect of transit time? BTL 3 Applying

13. Show the purpose of slow wave structures in TWT? BTL 3 Applying

14. Analyze phase focusing effect. BTL 4 Analyzing

15. Explain Hull cutoff condition? BTL 4 Analyzing

16. Infer the applications of magnetron. BTL 4 Analyzing

17. Determine the characteristics of Co-axial magnetron. BTL 5 Evaluating

18. Why magnetron is called as Cross field Devices? BTL 5 Evaluating

19. How would you explain BWO? State the applications of BWO. BTL 6 Creating

20. Elaborate on Bunching process. BTL 6 Creating

PART – B

1. (i)Write notes on high frequency limitations of conventional

vacuum devices. (8)

(ii)Examine in detail multicavity klystron amplifier. (8)

BTL 1 Remembering

2. (i)With the Applegate diagram, Describe the mechanism of

operation of two cavity klystron Amplifier. (8)

(ii)Derive the equation of velocity modulation and transit time

in drift space. (8)

BTL 1 Remembering

3. (i)Define bunching process and obtain optimum bunching

distance Lopt. (8)

(ii)Obtain output power, efficiency, mutual conductance and

voltage gain of klystron amplifier. (8)

BTL 1 Remembering

4. An identical two cavity Klystron amplifiers operates at 4GHz

with V0 =1 kV, Io=22mA, cavity gap 1mm, drift space 3 cms.

Calculate beam coupling coefficient, d.c. transit angle in drift

space and input cavity voltage magnitude for maximum output

voltage. (16)

BTL 1 Remembering

5. (i)Discuss the working principle of reflex klystron oscillator

with necessary diagrams. (8)

(ii)Derive velocity modulation, transit time of reflex klystron

oscillator. (8)

BTL 2 Understanding

6. (i)Summarize the power output mode curve/frequency

characteristics of reflex klystron. (8)

(ii)Draw the equivalent circuit and Obtain the electronic spiral

curve of reflex klystron. (8)

BTL 2 Understanding


7. How would you describe the π mode of oscillations of

Magnetron, what is meant by strapping in magnetron and why

it is done? (16)

BTL 2 Understanding

8. Illustrate with interaction region diagram the mechanism of

operation of TWT amplifier, its applications and the

expression for the gain of a TWT. (16)

BTL 3 Applying

9. (i) Demonstrate the role of slow wave structure in TWT and

give the comparison between two cavity Klystron amplifiers

with travelling wave tube. (8)

(ii)A helical TWT has diameter of 2mm with 50 turns per cm.

Calculate the axial phase velocity and anode voltage at which

TWT can be operated for useful gain. (8)

BTL 3 Applying

10. A helix TWT operates at 4GHz under a beam voltage 10KV

and beam current 500mA. If the helix impedance is 25 Ω and

the interaction length of 20cm, Find the O/P power gain in dB.

(16)

BTL 4 Analyzing

11. Explain the construction, operation, characteristics and

applications of BWO. (16)

BTL 4 Analyzing

12. Illustrate with neat sketch the cross sectional view of magnetron

tube and explain how bunching occurs with equations of

electron trajectory and derive the expression for Hull cut-off

voltage. (16)

BTL 4 Analyzing

13. A reflex klystron is operated at 9 GHz with dc beam voltage

600V, beam current 1 0mA, repeller space l e n g t h o f

1 m m for 1 ¾ mode, Beam coupling coefficient is assumed

to be 1. Calculate the repeller voltage, RF power output,

electronic efficiency and the b a n d w i d t h over ΔVR =

1V. (16)

BTL 5 Evaluating

14. (i) Can you explain different types of magnetron oscillators(8)

(ii) An X band pulsed cylindrical magnetron has Anode

voltage V0=25KV, Beam current I0=25A, Magnetic flux

density B0=0.34wb/m2 , radius of cathode cylinder a=5cm and

radius of vane edge to center b=10cm. Determine cyclotron

angular frequency, cutoff voltage for a fixed B0 and cutoff

magnetic flux density for a fixed V0. (8)

BTL 6 Creating

UNIT V MICROWAVE MEASUREMENTS


Measuring Instruments : Principle of operation and application of VSWR meter, Power meter, Spectrum

analyzer, Network analyzer, Measurement of Impedance, Frequency, Power, VSWR, Q-factor, Dielectric

constant, Scattering coefficients, Attenuation, S-parameters.

PART A

Q.No Questions BT

Level

Domain

1. Quote the difference between Scalar and Vector network

analyzers.

BTL 1 Remembering

2. What is the significance behind dielectric constant

measurement?

BTL 1 Remembering

3. Tell about wave meter method of measurement of frequency.

BTL 1 Remembering

4. Name two sensors used for microwave power measurement. BTL 1 Remembering

5. List the main errors in the measurement of attenuation at

microwave frequency?

BTL 1 Remembering

6. Show the need for matching network? BTL 1 Remembering

7. Summarize the basic design considerations for the proper

operation of a spectrum Analyzer?

BTL 2 Understanding

8. Describe the three scales on the VSWR meter. BTL 2 Understanding

9. Interpret the methods used for frequency measurement BTL 2 Understanding

10. Differentiate barretter and thermistor.

BTL 2 Understanding

11. Explain tunable detector BTL 3 Applying

12. Show how the S-parameter of a microwave circuit measured? BTL 3 Applying

13. Demonstrate the errors possible in VSWR measurements. BTL 3 Applying

14. Explain how to measure dielectric measurement of a solid?

BTL 4 Analyzing

15. Analyze the methods employed to measure cavity Q? BTL 4 Analyzing

16. Infer some application of spectrum analyzer. BTL 4 Analyzing

17. Determine what is network analyzer BTL 5 Evaluating

18. How will you determine the VSWR and return loss in

reflectometer method.

BTL 5 Evaluating

19. Discuss the different types of Impedance measurement

BTL 6 Creating


methods?

20. Can you elaborate the main purpose of slotted section with line

carriage?

BTL 6 Creating

PART – B

1. (i)Describe the construction of Tunable detector and Slotted

line carriage. (8)

(ii)Examine Spectrum analyzer and Network analyzer with

suitable diagrams. (8)

BTL 1 Remembering

2. Write notes on power sensors used for microwave power

measurements. (16)

BTL 1 Remembering

3. (i)Show the principle of power meter bridge circuit. (8)

(ii)Identify how high power measurements are done using

calorimetric method. (8)

BTL 1 Remembering

4. Tell with the block diagram the steps involved for the

insertion loss and power ratio method of attenuation

measurement. (16)

BTL 1 Remembering

5. With the experimental setup describe return loss measurement

by reflectometer method. (16)

BTL 2 Understanding

6. Summarize the slotted line method of VSWR measurement

and explain how to measure low values of VSWR. (16)

BTL 2 Understanding

7. Describe the measurement of high VSWR by double minima

method with the help of block diagram. (16)

BTL 2 Understanding

8. (i)Illustrate the procedure to measure the impedance of a Load

using slotted line method. (8)

(ii) Examine the measurement of impedance of a discontinuity

and measurement of impedance by reflectometer. (8)

BTL 3 Applying

9. Classify and explain the three ways of frequency measurement

techniques? (16)

BTL 3 Applying

10. Explain the impedance, wavelength and frequency

measurement using slotted line method. (16)

BTL 4 Analyzing

11. Analyze about cavity Q. Also explain slotted line method and

reflectometer method of measurement of Q. (16)

BTL 4 Analyzing


12. Explain in detail about the measurement of Q from

transmitted power measurement. (16)

BTL 4 Analyzing

13. How would you determine dielectric constant, explain with

block diagram. (16)

BTL 5 Evaluating

14. (i)Can you formulate a method for the calculation of S

parameter of a two port network? (8)

(ii)How would you calculate the S parameter of a four port

network- say for a magic Tee. (8)

BTL 6 Creating

valliammai engineering college semester/ec6701-rf and... · ec 6701 rf and microwave engineering...

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