JNTU Kakinada B-Tech 3-2 RT32044 I MICROWAVE ENGINEERING R13 April 2018 Question Paper

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING (Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) List out the various IEEE Microwave frequency bands. [3M]
b) What are the applications of Micro strip lines? [4M]
c) Write the properties of S-parameters. [4M]
d) What is meant by velocity modulation? [3M]
e) Draw the ?-? diagram for a helical structure and explain its significance. [4M]
f) Write short notes on two-valley theory. [4M]
PART -B
2 a) Derive the TE
mn
field equations in rectangular waveguide. [8M]
b) Write short notes on phase velocity and group velocity.
[8M]
3 a) Derive the expressions for field equations of TM modes in circular waveguide. [8M]
b) With necessary equations, explain about rectangular cavity resonator.
[8M]
4 a) What is magic tee? Derive the S matrix of a Magic Tee. [8M]
b) Explain the various construction methods and applications of circulator.
[8M]
5 a) What are the limitations of conventional tubes at microwave frequencies? Explain. [8M]
b) A reflex klystron operates under the following conditions:
V
0
= 600 V, L = 1 mm, R
sh
= 15 k?, e/m = 1.759 x 10
11
, f
r
= 9 GHz. The Tube is
oscillating at f
r
at the peak of the n = 2 mode or
4
3
1 mode. Assume that the transit
time through the gap and beam loading can be neglected.
i) Find the value of the repeller voltage V
r
.
ii) Find the direct current necessary to give a microwave gap voltage of 200 V.
iii) What is the electronic efficiency under this condition?
[8M]
6 a) Derive the expression for Axial Electric field in helix type travelling wave tube. [8M]
b) Explain the operation of Magnetron and write its applications.
[8M]
7 a) Discuss about construction and operation of TRAPATT diode. [8M]
b) Draw the general set-up of microwave bench and explain the purpose of each
block.
[8M]
*****
R13
SET – 1

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING (Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) List out the various IEEE Microwave frequency bands. [3M]
b) What are the applications of Micro strip lines? [4M]
c) Write the properties of S-parameters. [4M]
d) What is meant by velocity modulation? [3M]
e) Draw the ?-? diagram for a helical structure and explain its significance. [4M]
f) Write short notes on two-valley theory. [4M]
PART -B
2 a) Derive the TE
mn
field equations in rectangular waveguide. [8M]
b) Write short notes on phase velocity and group velocity.
[8M]
3 a) Derive the expressions for field equations of TM modes in circular waveguide. [8M]
b) With necessary equations, explain about rectangular cavity resonator.
[8M]
4 a) What is magic tee? Derive the S matrix of a Magic Tee. [8M]
b) Explain the various construction methods and applications of circulator.
[8M]
5 a) What are the limitations of conventional tubes at microwave frequencies? Explain. [8M]
b) A reflex klystron operates under the following conditions:
V
0
= 600 V, L = 1 mm, R
sh
= 15 k?, e/m = 1.759 x 10
11
, f
r
= 9 GHz. The Tube is
oscillating at f
r
at the peak of the n = 2 mode or
4
3
1 mode. Assume that the transit
time through the gap and beam loading can be neglected.
i) Find the value of the repeller voltage V
r
.
ii) Find the direct current necessary to give a microwave gap voltage of 200 V.
iii) What is the electronic efficiency under this condition?
[8M]
6 a) Derive the expression for Axial Electric field in helix type travelling wave tube. [8M]
b) Explain the operation of Magnetron and write its applications.
[8M]
7 a) Discuss about construction and operation of TRAPATT diode. [8M]
b) Draw the general set-up of microwave bench and explain the purpose of each
block.
[8M]
*****
R13
SET – 1

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING
(Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B)2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) List out the applications of microwaves. [3M]
b) Sketch the schematic diagram of strip lines. [3M]
c) Write short notes on tuning screws. [4M]
d) Draw the Applegate diagram with gap voltage for a reflex klystron and explain it. [4M]
e) Write the advantages of travelling wave tubes. [4M]
f) Write the differences between transferred electron devices and avalanche transit
time devices.
[4M]
PART -B
2 a) Derive the equation for the solution to the Helmholtz equation in rectangular
coordinates.
[8M]
b) Discuss about the impossibility of TEM mode in Waveguides.
[8M]
3 a) Explain about quality factor of Micro strip lines. [8M]
b) With necessary expressions, explain about circular cavity resonator.
[8M]
4 a) What are the various applications of Magic Tee? Explain. [8M]
b) What are ferrites? How they are useful in microwaves? Explain faradays rotation?
[8M]
5 a) With necessary equations, explain the velocity modulation process in two cavity
klystron amplifier.
[8M]
b) Define Electronic Admittance of a reflex klystron and explain it with necessary
equations.
[8M]
6 a) Discuss about Helical slow-wave structure in microwave tubes. [8M]
b) Derive the Hull cutoff magnetic equation and Hull cutoff voltage equation.
[8M]
7 a) Explain the operation of IMPATT diode. [8M]
b) Define VSWR and explain the procedure for measurement of VSWR. [8M]
*****
R13
SET – 2

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING (Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) List out the various IEEE Microwave frequency bands. [3M]
b) What are the applications of Micro strip lines? [4M]
c) Write the properties of S-parameters. [4M]
d) What is meant by velocity modulation? [3M]
e) Draw the ?-? diagram for a helical structure and explain its significance. [4M]
f) Write short notes on two-valley theory. [4M]
PART -B
2 a) Derive the TE
mn
field equations in rectangular waveguide. [8M]
b) Write short notes on phase velocity and group velocity.
[8M]
3 a) Derive the expressions for field equations of TM modes in circular waveguide. [8M]
b) With necessary equations, explain about rectangular cavity resonator.
[8M]
4 a) What is magic tee? Derive the S matrix of a Magic Tee. [8M]
b) Explain the various construction methods and applications of circulator.
[8M]
5 a) What are the limitations of conventional tubes at microwave frequencies? Explain. [8M]
b) A reflex klystron operates under the following conditions:
V
0
= 600 V, L = 1 mm, R
sh
= 15 k?, e/m = 1.759 x 10
11
, f
r
= 9 GHz. The Tube is
oscillating at f
r
at the peak of the n = 2 mode or
4
3
1 mode. Assume that the transit
time through the gap and beam loading can be neglected.
i) Find the value of the repeller voltage V
r
.
ii) Find the direct current necessary to give a microwave gap voltage of 200 V.
iii) What is the electronic efficiency under this condition?
[8M]
6 a) Derive the expression for Axial Electric field in helix type travelling wave tube. [8M]
b) Explain the operation of Magnetron and write its applications.
[8M]
7 a) Discuss about construction and operation of TRAPATT diode. [8M]
b) Draw the general set-up of microwave bench and explain the purpose of each
block.
[8M]
*****
R13
SET – 1

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING
(Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B)2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) List out the applications of microwaves. [3M]
b) Sketch the schematic diagram of strip lines. [3M]
c) Write short notes on tuning screws. [4M]
d) Draw the Applegate diagram with gap voltage for a reflex klystron and explain it. [4M]
e) Write the advantages of travelling wave tubes. [4M]
f) Write the differences between transferred electron devices and avalanche transit
time devices.
[4M]
PART -B
2 a) Derive the equation for the solution to the Helmholtz equation in rectangular
coordinates.
[8M]
b) Discuss about the impossibility of TEM mode in Waveguides.
[8M]
3 a) Explain about quality factor of Micro strip lines. [8M]
b) With necessary expressions, explain about circular cavity resonator.
[8M]
4 a) What are the various applications of Magic Tee? Explain. [8M]
b) What are ferrites? How they are useful in microwaves? Explain faradays rotation?
[8M]
5 a) With necessary equations, explain the velocity modulation process in two cavity
klystron amplifier.
[8M]
b) Define Electronic Admittance of a reflex klystron and explain it with necessary
equations.
[8M]
6 a) Discuss about Helical slow-wave structure in microwave tubes. [8M]
b) Derive the Hull cutoff magnetic equation and Hull cutoff voltage equation.
[8M]
7 a) Explain the operation of IMPATT diode. [8M]
b) Define VSWR and explain the procedure for measurement of VSWR. [8M]
*****
R13
SET – 2

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING
(Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B)2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) What is meant by mode of a electromagnetic wave in waveguide? [3M]
b) Write the applications of circular waveguide. [4M]
c) Define Coupling Factor and Directivity of a Directional Coupler. [3M]
d) List out the characteristics of two-cavity klystron amplifier. [4M]
e) What is the purpose of slow-wave structures in microwave tubes? Explain. [4M]
f) Write short notes on Low Frequency Measurement versus Microwave
Measurements.
[4M]
PART -B
2 a) Derive the wave equation for a TM wave and obtain all the field components in a
rectangular waveguide.
[8M]
b) An air filled rectangular waveguide of inside dimensions 7 x 3.5 cm operates in the
dominant TE
10
mode.
(i) Find the cut off frequency. (ii) Determine the phase velocity of the wave in the guide at a frequency of 3.5 GHz.
[8M]
3 a) Discuss about ohmic losses in Micro strip lines. [8M]
b) Explain about Q factor of a Cavity Resonator.
[8M]
4 a) Derive the S-Matrix of H-Plane Tee. [8M]
b) Explain the different types of Microwave attenuators.
[8M]
5 a) What is meant by Reentrant Cavities? How they are useful in microwaves? Explain. [8M]
b) Explain the operation of reflex klystron and write its performance characteristics.
[8M]
6 a) Explain the nature of four propagation constants in helix travelling-wave tube. [8M]
b) Discuss about power output and efficiency of magnetron.
[8M]
7 a) Explain about Gunn Oscillation modes. [8M]
b) Explain the procedure for measurement of Attenuation. [8M]
*****
R13
SET – 3

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING (Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) List out the various IEEE Microwave frequency bands. [3M]
b) What are the applications of Micro strip lines? [4M]
c) Write the properties of S-parameters. [4M]
d) What is meant by velocity modulation? [3M]
e) Draw the ?-? diagram for a helical structure and explain its significance. [4M]
f) Write short notes on two-valley theory. [4M]
PART -B
2 a) Derive the TE
mn
field equations in rectangular waveguide. [8M]
b) Write short notes on phase velocity and group velocity.
[8M]
3 a) Derive the expressions for field equations of TM modes in circular waveguide. [8M]
b) With necessary equations, explain about rectangular cavity resonator.
[8M]
4 a) What is magic tee? Derive the S matrix of a Magic Tee. [8M]
b) Explain the various construction methods and applications of circulator.
[8M]
5 a) What are the limitations of conventional tubes at microwave frequencies? Explain. [8M]
b) A reflex klystron operates under the following conditions:
V
0
= 600 V, L = 1 mm, R
sh
= 15 k?, e/m = 1.759 x 10
11
, f
r
= 9 GHz. The Tube is
oscillating at f
r
at the peak of the n = 2 mode or
4
3
1 mode. Assume that the transit
time through the gap and beam loading can be neglected.
i) Find the value of the repeller voltage V
r
.
ii) Find the direct current necessary to give a microwave gap voltage of 200 V.
iii) What is the electronic efficiency under this condition?
[8M]
6 a) Derive the expression for Axial Electric field in helix type travelling wave tube. [8M]
b) Explain the operation of Magnetron and write its applications.
[8M]
7 a) Discuss about construction and operation of TRAPATT diode. [8M]
b) Draw the general set-up of microwave bench and explain the purpose of each
block.
[8M]
*****
R13
SET – 1

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING
(Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B)2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) List out the applications of microwaves. [3M]
b) Sketch the schematic diagram of strip lines. [3M]
c) Write short notes on tuning screws. [4M]
d) Draw the Applegate diagram with gap voltage for a reflex klystron and explain it. [4M]
e) Write the advantages of travelling wave tubes. [4M]
f) Write the differences between transferred electron devices and avalanche transit
time devices.
[4M]
PART -B
2 a) Derive the equation for the solution to the Helmholtz equation in rectangular
coordinates.
[8M]
b) Discuss about the impossibility of TEM mode in Waveguides.
[8M]
3 a) Explain about quality factor of Micro strip lines. [8M]
b) With necessary expressions, explain about circular cavity resonator.
[8M]
4 a) What are the various applications of Magic Tee? Explain. [8M]
b) What are ferrites? How they are useful in microwaves? Explain faradays rotation?
[8M]
5 a) With necessary equations, explain the velocity modulation process in two cavity
klystron amplifier.
[8M]
b) Define Electronic Admittance of a reflex klystron and explain it with necessary
equations.
[8M]
6 a) Discuss about Helical slow-wave structure in microwave tubes. [8M]
b) Derive the Hull cutoff magnetic equation and Hull cutoff voltage equation.
[8M]
7 a) Explain the operation of IMPATT diode. [8M]
b) Define VSWR and explain the procedure for measurement of VSWR. [8M]
*****
R13
SET – 2

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING
(Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B)2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) What is meant by mode of a electromagnetic wave in waveguide? [3M]
b) Write the applications of circular waveguide. [4M]
c) Define Coupling Factor and Directivity of a Directional Coupler. [3M]
d) List out the characteristics of two-cavity klystron amplifier. [4M]
e) What is the purpose of slow-wave structures in microwave tubes? Explain. [4M]
f) Write short notes on Low Frequency Measurement versus Microwave
Measurements.
[4M]
PART -B
2 a) Derive the wave equation for a TM wave and obtain all the field components in a
rectangular waveguide.
[8M]
b) An air filled rectangular waveguide of inside dimensions 7 x 3.5 cm operates in the
dominant TE
10
mode.
(i) Find the cut off frequency. (ii) Determine the phase velocity of the wave in the guide at a frequency of 3.5 GHz.
[8M]
3 a) Discuss about ohmic losses in Micro strip lines. [8M]
b) Explain about Q factor of a Cavity Resonator.
[8M]
4 a) Derive the S-Matrix of H-Plane Tee. [8M]
b) Explain the different types of Microwave attenuators.
[8M]
5 a) What is meant by Reentrant Cavities? How they are useful in microwaves? Explain. [8M]
b) Explain the operation of reflex klystron and write its performance characteristics.
[8M]
6 a) Explain the nature of four propagation constants in helix travelling-wave tube. [8M]
b) Discuss about power output and efficiency of magnetron.
[8M]
7 a) Explain about Gunn Oscillation modes. [8M]
b) Explain the procedure for measurement of Attenuation. [8M]
*****
R13
SET – 3

Code No: RT32044
III B. Tech II Semester Regular/Supplementary Examinations, April -2018
MICROWAVE ENGINEERING
(Electronics and Communication Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B)2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
*****
PART ?A
1 a) Define cutoff frequency and write its significance. [3M]
b) Write the expressions for resonant frequencies in rectangular and circular cavity
resonators.
[3M]
c) Write short notes on Microwave Isolator. [4M]
d) What are the applications of reflex klystrons? [4M]
e) Write the major differences between the TWT and the Klystron. [4M]
f) List out the performance characteristics of IMPATT diode. [4M]
PART -B
2 a) Derive the expressions for the characteristic impedance and wavelength in the guide
for TE and TM modes.
[8M]
b) Discuss about the power losses in rectangular waveguide.
[8M]
3 a) Derive the expression for the solution of Helmholtz equation in cylindrical
coordinates.
[8M]
b) Explain about Dielectric losses in Micro strip lines.
[8M]
4 a) Define a Microwave junction. Explain how it is described by using S-Parameters. [8M]
b) Derive the S-Matrix of a Directional Coupler.
[8M]
5 a) With necessary equations, explain the bunching process in 2 ? cavity klystron
amplifiers.
[8M]
b) Derive the expression for power output and efficiency of reflex klystron.
[8M]
6 a) Draw the diagram of helix travelling-wave tube and explain its operation. [8M]
b) An X-band pulsed cylindrical magnetron has the following operating parameters:
Anode voltage = 26 kV, Beam current = 27 A, magnetic flux density = 0.336
Wb/m
2
, radius of cathode cylinder = 5 cm, Radius of vane edge to center b = 10 cm.
compute
i) The cyclotron angular frequency
ii) The cutoff voltage for a fixed B
0
iii) The cutoff magnetic flux density for a fixed V
0
.
[8M]
7 a) Explain the concept of Gunn effect with necessary figures. [8M]
b) Explain the procedure for impedance measurement. [8M]

R13
SET – 4