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SIDDHARTH GROUP OF INSTITUTIONS :: PUTTUR
Siddharth Nagar, Narayanavanam Road – 517583
QUESTION BANK (OBJECTIVE)
Subject with Code : MWE (13A04603)
Year & Sem: III-B.Tech & II-Sem
Course & Branch: B.Tech - ECE
Regulation: R13
Unit-1
Waveguides and Resonators
1. Microwave frequency range is -----(a) 1 Khz-100 Khz
(b)1 Mhz-100 Mhz
(c) Radar
(b) Microwave oven
[
]
[
]
(d) Satellite
3. ---- is an electronically controlled home appliance used for cooking
(a)Radar
]
(c) 1 Ghz-1000 Ghz (d) None
2. --- is a Object detection System that uses microwaves
(a) Microwave oven (b) Transmitter
[
(c) Satellite
(d) None
4. In --- Wave Both A & B electric and magnetic fields are purely transverse
[
]
(a) TE
(b) TM
(c) TEM
(d) None
5. --- is hollow metallic tube used for Transmitting EM waves
[
]
[
]
[
]
[
]
[
]
[
]
[
]
[
]
[
]
14. The distance travelled by the wave in order to undergo a phase shift of 3600 called as--[
]
(a) Strip line
(b) Micro strip line
(c) Waveguide (d) None
6. Minimum possible mode for TM modes is ----(a)TM00
(b) TM01
(c) TM10
(d) TM11
7. Minimum possible mode for TE modes is ---(a) TE00
(b) TE01
(c) TE10
(d) b & c
8. Waveguide acts as ---- filter
(a) Low pass
(b) Band reject
(c) Band pass
(d) High pass
9. Speed of EM wave in free space is -----(a) 3 x 1010m/s
(b) 3 x 1012cm/s
(c) 3 x 1010cm/s
(d) None
10. The mode having highest cut-off wavelength is called as ---(a) Dominant mode
(b) Degenerate mode
(c) Both A & B
(d) None
11. The mode having lowest cut-off frequency is called as ---(a) Dominant mode
(b) Degenerate mode
(c) Both A & B
(d) None
12. ---- is dominant mode for TM waves in rectangular waveguide
(a) TM00
(b) TM01
(c) TM11
(d) TM11
13. --- is dominant mode for TE waves when a > b in rectangular waveguide
(a) TE00
(a) Phase velocity
(b) TE10
(b) group velocity
(c) TE01
(c) guide wavelength
(d) TE11
(d) None
15. -----is the relation between λg and β
(a) β =2πλg
(b) β =πλg
(c) β =2π/λg
(b) Vp = w β
(c) Vp = β / w
]
[
]
(d) None
16. --- is relation between Vp and β
(a) Vp = w/ β
[
(d) None
17. --- is relation between Vg and β
(a) Vg = dw/ dβ
(c) Vg = wβ
(b) Vg = w/β
(b) Speed of light
(c) Speed of sound
(b) 20 – 20 Khz
(c) 1 Mhz – 10 Mhz
(b) 20 – 20 Khz
(c) 1 Mhz – 10 Mhz
(b) Thevenin’s
(c) Norton’s
(b) TM
(c)TEM
(c) Tank circuit
(b) λg
(c) λg/4
(b) Amplifier
(c) Oscillator
(b) BW= fr / Q
(c) BW= fr x Q2
(b) 1 m
(c) 2 m
(b) filter
(c) Both A & B
(b) High pass
]
[
]
[
]
[
]
[
]
[
]
[
]
[
]
(c) Tank circuit (d) None
30. If λ = 1m then f= ---(a) 300 Mhz
[
(d) None
29. At low frequencies cavity resonator works similar to ----(a) Low pass
]
(d) None
28. Cavity resonators used in ----(a)Oscillator
[
(d) None
27. If f = 600 Mhz then λ= ---(a) 0.5 m
]
(d) None
26. ------ is the relation between Q, fr & BW
(a)BW= fr x Q
[
(d) λg/3
25. ---- is a measure of frequency selectivity of resonant or anti resonant circuit
(a)Q factor
]
(d) None
24. In cavity resonators, distance between shorting end plates is multiple of --(a) λg/2
[
(d) TE & TM
23. ----- is a metallic enclose formed by shorting two ends of waveguide
(a) Cavity Resonator (b) Amplifier
]
(d) None
22. Rectangular waveguide supports ---- waves
(a) TE
[
(d) None
21. --- theorem used for calculating power transmission and power losses
(a)Pointing
]
(d) None
20. Frequency range of audio signal is ----(a) 0 – 4 Khz
[
(d) None
19. Frequency range of voice signal is -----(a) 0 – 4 Khz
]
(d) None
18. Product of Phase velocity and group velocity is --(a) Square of speed of light
[
(b) 3 x 108 hz
(c) Both A & B
31. In Microwave we take the elements as
(a) Lumped circuit elements
(b) Distributed circuit elements
(c) Both A & B
(d) None
32. For handling large microwave power, the best medium is
(a) Coaxial line
(b) Rectangular waveguide
(c) Strip line
(d) Circular waveguide
33. Which of the following noise becomes important at microwave frequencies
(a) Shot noise
(b) Flicker noise
(c) Thermal noise
(d) Transit time noise
(d) None
[
]
[
]
[
]
34. The phenomenon of microwave signals following the curvature of earth is known as [
(a) Faraday effect
(b) Ducting
(c) Wave tilt
(d) Troposcatter
35. Microwave frequency range extends from
(a) 3 MHz to 30 MHz
(b) 30 MHz to 300 MHz
(c) 300 MHz to 3000 MHz
(d) 500 MHz to 30000 MHz
36. Due to curvature of earth, microwave repeaters are placed at a distance of about
(a) 10 Km
(b) 50 Km
(c) 150 Km
(b) Large
[
]
[
]
(d) 250 Km
37. At microwave frequencies the size of the antenna becomes
(a) Very large
(c) Small
[
]
[
]
(d) Very Small
38. Short term fading in microwave communication links can be overcome by
(a) Increasing the transmitted power
(b) Changing the antenna
(c) Changing the modulation scheme
(d) Diversity reception and transmission
39. ---- is a process used for monitoring and controlling the vehicle.
(a) Radar
(b) Modulation
(c) Navigation
[
(b) Medium Waves
(c) Short Waves
]
(d) Microwave Oven
40. RADAR is a Object detection System that uses ---(a) Long Waves
]
[
]
(d) Satellite
SHORT QUESTIONS
1. Define Microwave and list the applications of microwave.
[L1][CO.1][2M]
2. Describe IEEE microwave bands.
[L2][CO.1][2M]
3. List the advantages of microwaves.
[L1][CO.1][2M]
4. Define Wave guide and guide wave length.
[L1][CO.1][2M]
5. Expalin cut-off wave length for RWG.
[L2][CO.1][2M]
6. Define dominant mode with respect to a waveguide. Mention dominant mode for Rectangular and
circular waveguides.
[L1][CO.1][2M]
7. If the broader dimension of a rectangular waveguide is 2.2cms, what is the cut-off Frequency and
wavelength for dominant mode?
[L4][CO.1][2M]
8. Is a waveguide equivalent to a high pass filter or a low pass filter? Explain
[L2][CO.1][2M]
9. In the notation TEmn and TMmn what do m and n represent?
[L1][CO.1][2M]
10. What is cavity resonator? List the types of cavity resonators.
[L1][CO.1][2M]
11. What is the two boundary conditions must be met in a waveguide for a Wave to travel down the guide?
[L1][CO.1][2M]
12. Define group velocity?
[L2][CO.1][2M]
13. What is Waveguide? What are advantages Waveguide over coaxial cable?
[L1][CO.1][2M]
14. What are the major bands available in microwave frequencies?
[L1][CO.1][2M]
15. Calculate the cut-off frequency of the following modes in a square waveguide 4 cm × 4 cm TE10,
TM11.
[L3][CO.1][2M]
16. Show that TM01 and TM10 modes in a rectangular waveguide do not exist.
[L1][CO.1][2M]
17. Define wave impedance.
[L1][CO.1][2M]
18. Write short notes on “Cavity resonators and its applications”.
[L1,L6][CO.1][2M]
19. Define TEM, TE, and TM modes?
[L1][CO.1][2M]
20. A rectangular wave guide has a = 4 cm, b = 3 cm as its sectional dimensions. Find all the modes which
will propagate at 500 MHz.
[L5][CO.1][2M]
ESSAY QUESTIONS
1
(a) Discuss how the microwave spectrum is categorized into different bands.
[L2][CO.1][4M]
(b) What is the need of microwave frequency? Explain different applications of Microwaves.
[L1,L2][CO.1][6M]
2
(a) Explain the wave impedance of a rectangular waveguide and derive the expression for the wave
impedance of TE and TM modes.
[L][CO.1][6M]
(b) Calculate the cut-off frequency of the following modes in a square waveguide 4 cm × 4 cm TE10,
TM11 and TE22.
3
[L4][CO.1][4M]
(a) Show that a waveguide works like a high pass filter.
[L1][CO.1][5M]
(b) A waveguide having dimensions a = 5 cm, b = 2 cm. The signal applied to waveguide
is10GHz. Determine the modes that are propagating in the waveguide.
4
[L4][CO.1][5M]
Derive the expressions for the field components due to TE waves in rectangular wave guide.
[L4][CO.1][10M]
5
Explain following terms (a) Guide wavelength (b) Phase Velocity (c) Group Velocity.[L2][CO.1][10M]
6
(a) Show that TM01 and TM10 modes in a rectangular waveguide do not exist. [L1][CO.1][4M]
(b) For a wave guide having cross section 3cm × 2cm, compute the cut-off frequency in the TE01
mode. Also, calculate the phase velocity and guide wavelength at a frequency equal to 50% above the
cut-off frequency.
7
[L4][CO.1][6M]
(a) Why TEM modes are not possible in hollow rectangular waveguide? Prove it[L3][CO.1][6M]
(b) When dominant mode propagated in air filled circular waveguide diameter is 4 cms.
Find cut-off wavelength, cut-off frequency and guide wavelength.
[L4][CO.1][4M]
8 (a) Define Cavity Resonator. Draw Diagrams of Rectangular & circular cavity Resonators.
[L1][CO.1][4M]
9
(b) Derive the equation for resonant frequency in circular cavity resonator.
[L4][CO.1][6M]
(a) Derive the equation for Resonant frequency in rectangular cavity resonator.
[L4][CO.1][5M]
(b) Calculate resonant frequency of rectangular cavity filled with dielectric with €r=4 and having
dimensions a=5cm b=4cm and d=15cm.
10 (a) Discuss in detail about Q factor of cavity Resonator.
[L4][CO.1][5M]
[L1][CO.1][4M]
(b) A wave guide operating in TE10 mode has dimensions a = 2.26 cm and b = 1 cm. The measured
guide wave length is 4 cm. Find
i. Cut off frequency of the propagating mode
ii. The frequency of operation
iii. Maximum frequency of propagation in this mode.
[L4][CO.1][6M]
SIDDHARTH GROUP OF INSTITUTIONS :: PUTTUR
Siddharth Nagar, Narayanavanam Road – 517583
QUESTION BANK (OBJECTIVE)
Subject with Code : MWE (13A04603)
Year & Sem: III-B.Tech & II-Sem
Course & Branch: B.Tech - ECE
Regulation: R13
Unit-2
Waveguide Components
1. ---- used for producing field intensities in the waveguide
(a) Probe
(b) loop
[
(c) Both A & B
(d) None
2. Probe used for setting ---- field in the waveguide
(a) Electric
[
(b) Magnetic
(c) Both A & B
[
(b) Magnetic
(c) Both A & B
[
(b) Posts
(c) Screw
6.
(b) Pure resistor
(c) Inductively
(b) Pure resistor
(c) Inductively
(b) Posts
(c) Screw
(b) Half
(c) Maximum
(b) Half
(c) Maximum
(b) Variable
(c) Half
(b) Maximum
(c) Zero
(b) Series
(c) Both A & B
(b) Series
(c) Both A & B
(b) Hybrid Tee
(c) E-H Plane Tee
(b) Three
(c) Four
]
[
]
[
]
[
]
]
(d) None
[
]
[
]
(d) All
16. Directional coupler is ----- port network
(a) Two
[
[
15. Combination of E-plane & H-plane Tee called as ----(a) Magic Tee
]
(d) None
14. E-plane junction also called as ---- junction
(a) Parallel
[
(d) None
13. H-plane junction also called as ---- junction
(a) Parallel
]
(d) None
12. In dielectric slab phase shifter, when slab placed inside completely phase shift is (a) Minimum
[
(d) None
11. Rotary vane attenuator provides ---- attenuation
(a) Fixed
]
(d) None
9. In Vane type attenuator ,when vane at center attenuation is ----10. Minimum
[
(d) Attenuator
8. In Flap attenuator, resistive card inserted completely in waveguide attenuation is (a) Minimum
]
(d) None
7. ---- used for reducing power of the signal
(a) Windows
[
(d) None
When h < λg/4 Screw behaves like -----(a) Capacitevely
]
(d) All
5. When h > λg/4 post behaves like -----(a) Capacitevely
]
(d) None
4. For Impedance matching we use ----(a) Windows
]
(d) None
3. loop used for setting ---- field in the waveguide
(a) Electric
]
(d) Five
17. - used for sampling small amount of microwave power used for measurement purpose [
(a) Gyrator
(b) Isolator
(c) Circulator
(d) None
18. Coupling loop placed along ---- dimensions of the waveguide
(a) Narrow
(b) Broader
[
(c) Both A & B
(c) Isolator
(b) Directivity
(c) Isolation
(b) Directivity
(c) Isolation
(b) FET
(c) Diode
(b) Reciprocal
(c) Modulation
(b) 1014
(c) 1016
(b) 1800
(c) 900
(b) 1800
[
]
[
]
[
]
[
]
[
]
[
]
(d) None
25. Gyrator provides ---- phase shift from port 2 to port 1
(a)00
]
(d) None
24. Gyrator provides ---- phase shift from port 1 to port 2
(a)00
[
(d)None
23. Ferrites resistivity is ----- times greater than metal
(a) 1012
]
(d) Transistor
22. Ferrites exhibits ----- property
(a) Non-Reciprocal
[
(d) None
21. ---- is a compound composed of MeO.Fe2O3
(a) Ferrites
]
(d) None
21. --- is the ratio of forward power to back power
(a) Coupling facto
[
(d) Circulator
20. ----- Is the ratio of incident power to forward power
(a) Coupling factor
]
(d) None
19. ---- used for measuring incident power
(a) Directional coupler (b) Gyrator
]
(c) 900
(d) None
26. A magic-Tee is nothing but
(a) A modification of E-plane tee
(b) A modification of H-plane tee
(c) A combination of E-Plane and H-Plane
(d) Two E-plane tees connected in parallel
27. For some application circular waveguide may be preferred over rectangular because [
]
(a) The smaller cross section needed at any frequency
(b) Lower attenuation
(c) Freedom from spurious modes
(d) Rotation of polarization
28. Indicate which of the following cannot be followed by the word waveguide
(a) Elliptical
(b) Flexible
(c) Coaxial
(b) Ridged
(c) Rectangular
(b) C=I+D
(c) D=I+C
(b) Iris
(c) Stub
(b) 2.45 GHz (c) 3.3 GHz
(b) S band
(c) L band
]
[
]
[
]
[
]
(d) 4.5 GHz
33. Aircraft surveillance radars mostly operate in
(a) C band
[
(d) Plunger
32. A frequency at which microwave ovens operate is
(a) 50 μHz
]
(d) I=CD
31. The waveguide tuning component, which is not easily adjustable, is
(a) Screw
[
(d) Flexible
30. In a directional coupler
(a) I = C+D
]
(d) Ridged
29. In order to reduce cross sectional dimensions, the waveguide to use is
(a) Circular
[
(d) X band
34. Which of the following materials are generally preferred for waveguides?
[
(a) Cast iron and steel
(b) Nonmetallic solids including plastic
(c) High carbon steel and vanadium steel
(d) Brass and aluminum
35. A microwave component which is used to interconnect two sections of waveguide is the[
(a) T section
(b) Curved section
(c) Choke joint
[
(b) Copper and Iron
(c) Copper and Aluminum
(b) 2-4 Ghz
(c) 4-8 Ghz
(b) 2-4 Ghz
(c) 26-40 Ghz
(b) High pass
(c) Band pass
(b) E-Tee
(c) Magic Tee
[
]
[
]
[
]
(d) Band reject
40. The following Tee is used in front end of the micro wave receiver
(a)H-Tee
]
(d) 100-120 Ghz
39. Resonant Iris acts as ----- filter
(a) Low pass
[
(d) 8-12 Ghz
38. The range of frequencies in the Ku-band is ---(a)1-2 Ghz
]
(d) Copper and Tin
37. The range of frequencies in the X-band is ---(a)1-2 Ghz
]
(d) Tapered wedge
36. Brass is an alloy of
(a) Copper and Zinc
]
(d) None
SHORT QUESTIONS
1. What is attenuator and mention different attenuator?
[L1][CO.2][2M]
2. Define directivity and coupling factor of a directional coupler.
[L1][CO.2][2M]
3. What are the properties of ideal directional coupler?
[L1][CO.2][2M]
4. Define isolator and what is the use?
[L1][CO.2][2M]
5. What is Faraday rotation and list the ferrite devices.
[L1][CO.2][2M]
6. What is a circulator? And write applications of circulators.
[L1,L3][CO.2][2M]
7. What is scattering matrix?
[L2][CO.2][2M]
8. Write about S matrix for magic tee and directional coupler.
[L1][CO.2][2M]
9. What is magic tee? And write applications of magic tee.
[L1,L3][CO.2][2M]
10. Explain Tee junction with two examples
[L2][CO.2][2M]
11. Write a brief not on micro-strip lines.
[L1][CO.2][2M]
12. Define magic tee with figure?
[L2][CO.2][2M]
13. Sketch a 4 port Hybrid junction. Justify that it is basically a 3 dB directional coupler.
[L1][CO.2][2M]
14. Why the S-parameters are used in microwaves?
[L2][CO.2][2M]
15. Write the properties of [S] matrix.
[L1][CO.2][2M]
16. Define tee junction Name some uses of waveguide tees.
[L1][CO.2][2M]
17. Give a note on directional couplers Name some uses of waveguide twists.
[L2][CO.2][2M]
18. Define directivity of directional coupler Mention the different types of directional couplers.
.
[L1][CO.2][2M]
19. Write the characteristics of a three port tee junction.
[L1][CO.2][2M]
20. What is H-plane and E-plane Tee?
[L1][CO.2][2M]
ESSAY QUESTIONS
1
(a) Explain the coupling mechanism of waveguide.
[L2][CO.2][4M]
(b) Explain the following (i) Waveguide windows (ii) Screws
[L2][CO.2][6M]
2
Explain the following (a) precision Variable attenuator (b) rotary vane attenuator. [L2][CO.2][10M]
3
Explain following terms (a)E-plane Tee (b) H-plane Tee (c) Magic Tee
4
(a) Draw a typical directional coupler and define directivity and coupling coefficient.[L1][CO.2][5M]
(b) An 20db directional coupler
gives 3 dbm in output power through coupled port. If the Isolation
specified as 55 dB, find the power available at the Isolated Port.
5
[L2][CO.2][10M]
[L4][CO.2][5M]
What is the principle of phase shifter? Draw the diagram of dielectric phase shifter and discuss the
working mechanism.
[L1,L4][CO.2][10M]
6
Explain following terms (a) Gyrator (b) Isolator
[L2][CO.2][10M]
7
(a) What is meant by normalized voltage and normalized current with respect to the microwave circuit
concept. Draw a neat sketch of a Magic Tee and obtain its S matrix. [L2,L4][CO.2][6M]
(b) List and Explain two applications of Magic Tee.
8 (a) Derive the S-matrix for E-plane junction.
(b) Explain the principle of Ferrite phase shifter.
9 (a) Derive the S-matrix for Magic Tee junction.
[L6][CO.2][4M]
[L4][CO.2][6M]
[L2][CO.2][4M]
[L4][CO.2][5M]
(b) A 20 dB coupler has a directivity of 30 dB. Calculate the value of isolation. [L4][CO.2][5M]
10 (a) Derive the S-matrix for directional coupler.
[L4][CO.2][5M]
(b) Using the properties of scattering matrix of a lossless, reciprocal microwave junction, prove that for
a four port network if all the four ports are matched, the device shall be a directional coupler. .
.
[L5][CO.2][5M]
SIDDHARTH GROUP OF INSTITUTIONS :: PUTTUR
Siddharth Nagar, Narayanavanam Road – 517583
QUESTION BANK (OBJECTIVE)
Subject with Code : MWE (13A04603)
Year & Sem: III-B.Tech & II-Sem
Course & Branch: B.Tech - ECE
Regulation: R13
Unit-3
Linear Beam Tubes
1. If frequency increases ,the inductive reactance will----(a) Decreases
(b) Increases
(c) Constant
(b) Inphase
(c) Both A & B
(b) Radiation Losses (c) Both A & B
(b) 58%
(c) 90%
(b) Amplitude
(c) Velocity
(b) Oscillator
(c) Phase shifter
(b) Frequency
(c) Current
(b) TWT
(c) Reflex klystron
(b) n-3/4
(c) n+1/4
10. If electron is subjected to +max of RF signal,
(a) Increases
(b) Decreases
(b) Narrow
(c) Both A & B
(b) Moving
(c) Both A & B
]
[
]
[
]
[
]
[
]
[
]
[
]
(d) None
12. In TWT the RF field is ----(a) Stationary
[
(d) None
11. TWT is ----- band amplifier
(a) Broad
]
(d) None
its velocity -----
(c) Constant
[
(d) None
9. In Reflex klystron the optimum transit time T= ----(a) n+3/4
]
(d) None
8. ------- is the variable frequency oscillator
(a) Two cavity klystron amplifier
[
(d) None
7. The multi cavity klystron amp can be used for improve----(a) Gain
]
(d) None
6. Basically reflex klystron is a ----(a) Amplifier
[
(d) 46%
5. The working principle of Klystron amplifier is -----modulation
(a) Frequency
]
(d) None
4. The efficiency of two cavity klystron amplifier is ----(a) 25%
[
(d) None
3. The use of proper shielding of tubes minimizes -----losses.
(a) Copper losses
]
(d) None
2. At high frequencies the Ip is-----with grid voltage
(a) Out of phase
[
(d) None
13. One of the reasons why vacuum tubes eventually fail at microwave frequencies is that their[
]
(a) Noise figure increases
(b) Transit time becomes too short
(c) Shunt capacitive reactance become too large
(d) Series inductive reactance become too small
14. Which of the following can be used for amplification of microwave energy?
(a) Travelling wave tube
(b) Magnetron
(c) Reflex Klystron
[
]
(d) Gunn diode
15. The major advantage of TWT over Klystron
(a) Higher gain
[
(b) Higher frequency
(c) Higher output
(d) Higher bandwidth
16. Which of the following noise becomes important at microwave frequencies
(a) Shot noise
(b) Flicker noise
(c) Thermal noise
]
[
]
(d) Transit time noise
17. Indicate the false statement .transit time in microwave tube will be reduced if
(a) The electrodes are brought together
(b) A higher anode current is used
(c) Multiple or coaxial leads are used
(d) The anode voltage is made large
18. The multicavity klystron
[
]
[
]
[
]
(a) Is not a good low level amplifier because of noise
(b) Has a high repeller voltage to ensure a rapid transit time
(c) Is not suitable for pulsed operation
(d) Needs a long transit time through the buncher cavity to ensure current modulation
19. Indicate the false statement. klystron amplifiers may use intermediate cavities to
(a) Prevent the oscillations that occurs in two cavity klystron
(b) Increase the bw
(c) Improve the power gain (d) Increase the efficiency of the klystron
20. The TWT is sometimes preferred to the multicavity klystron amplifier ,because the formar [
(a) Is more efficient
(b)Has a greater bw
(c) Has a higher number of modes
(d) Produces a higher o/p power
21. The primary purpose pf the helix in the TWT is
[
]
]
(a) Prevent the electron beam spreading in the long tube (b) Reduce axial velocity of the rf field
(c) Ensure broadband operation
(d) Reduce the noise figure
22. The attenuator in the TWT is used for
(a) Help focusing
[
(b) Prevent oscillations
]
(c) Prevent saturation (d) Increase gain
23. Periodic permanent magnet focusing is used with TWT t to
[
]
(a) Allow pulsed operation
(b) Improve electron bunching
(c) Avoid the bulk of an electromagnet
(d) Allow coupled cavity operation at the high frequency
24. Indicate which of the following is not a TWT slow wave structure
(a) Periodic permanent magnet
(b) Coupled cavity
(c) Helix
25. The glass tube of a TWT may be coated with aquatic to
(a) Help focusing
(b) Provide attenuation
(c) Improve bunching
26. A reflex Klystron functions as
(a) Microwave oscillator (b) Microwave amplifier (c) Both A & B
27. The modes in a reflex Klystron
(a) Give the same frequency but different transit times
(b) Result from excessive transit time across the resonator gap
(c) Are caused by spurious frequency modulation
(d) Are just for theoretical considerations
[
]
[
]
(d) Ring bar
(d) Increase gain
[
]
(d) A high gain cavity
[
]
28. In Microwave we take the elements as
(a) Lumped circuit elements
(b) Distributed circuit elements
(c) Both A & B
(d) None of the above
29. Which of the following can be used for amplification of microwave energy?
(a) Travelling wave tube
(b) Magnetron
(c) Reflex Klystron
(b) Higher frequency
(c) Higher output
(b) 50,000 MHz
(b) Magnetron
[
(c) 20,000 MHz
(c) Reflex klystron
(b) TWT
[
]
]
(d) Travelling-wave tube
[
(c) CFA
]
(d) 10,000 MHz
33. ------ is unlikely to be used as a pulsed device
(a) BWO
]
(d) Higher bandwidth
32. The microwave tube that uses buncher and catcher cavities is
(a) Klystron
[
[
31. Operating frequency of the reflex klystron is as high as
(a) 70,000 MHz
]
(d) Gunn diode
30. The major advantage of TWT over Klystron
(a) Higher gain
[
]
(d) Multi-cavity klystron
34. Which of the following statement is false? In microwave tubes Transit time will be reduced if[
]
(a) The electrodes are brought closer together
(b) Multiple or coaxial leads are used
(c) The anode voltage is made larger
(d) The anode current is made larger
35. What is the primary purpose of the helix in a travelling wave tube?
[
]
(a) To reduce noise figure
(b) To prevent the electron beam from spreading in the long tube
(c) To reduce the axial velocity of the RF field
(d) To ensure broadband operation
36. In multicavity Klystron additional cavities are inserted between buncher and catcher cavities to achieve[
(a).Higher Gain
(b).Higher Efficiency
(c).Higher Frequency (d).Higher Bandwidth
37. A space between two cavities in two cavity klystron is
(a).Drift space
(b).Free space
(c).Running apace
[
(b). Tuned Amplifier
]
(d).Normal space
38. TWT is
(a).Oscillator
]
[
]
[
]
(c). Wide band Amplifier
(d).Both A & B amplifier and Oscillator
39. Klystron oscillators are most often used in the frequency range of
(a). 300 to 3000 MHz (b) 3000 to 30000 MHz
(c) 30 to 30000 MHz (d) 10 to 10000 MHz
40. The main benefit of using microwaves is
[
(a) Lower-cost equipment
(b) Simpler equipment
(c) Greater transmission distances
(d) More spectrum space for signals
]
SHORT QUESTIONS
1. Write classifications microwave Tubes.
[L1][CO.3][2M]
2. Why conventional tubes does not used at microwave frequencies?
[L1][CO.3][2M]
3. What is transit time?
[L1][CO.3][2M]
4. Mention the applications of two cavity Klystron.
[L6][CO.3][2M]
5. What is velocity and current modulation in a reflex klystron?
[L1][CO.3][2M]
6. What is the operating frequency and power output of a reflex klystron?
[L1][CO.3][2M]
7. What are the applications of reflex klystron?
[L1][CO.3][2M]
8. List four types of slow wave structures.
[L1][CO.3][2M]
9. What is the purpose of slow wave structures used in TWT amplifiers?
[L1][CO.3][2M]
10. Define bunching.
[L2][CO.3][2M]
11. What are the assumptions for calculation of RF power in Reflex Klystron?
[L4][CO.3][2M]
12. Why do different modes of operation exist for a reflex klystron?
[L1][CO.3][2M]
13. What is the condition for oscillation in Reflex klystron?
[L1][CO.3][2M]
14. In klystron what is the use of collector?
[L1][CO.3][2M]
15. Explain the need for an attenuator in a TWT amplifier.
[L2][CO.3][2M]
16. Give the drawbacks of klystron amplifiers.
[L1][CO.3][2M]
17. How the klystron amplifier can act as klystron oscillator? What are the applications of klystron
amplifier?
[L1,L6][CO.3][2M]
18. Draw the voltage characteristics of Reflex klystron
[L1][CO.3][2M]
19. What are limitations of conventional tubes at microwave frequencies?
[L1][CO.3][2M]
20. What do you mean by O-type tubes? Name some O-type tubes.
[L1][CO.3][2M]
ESSAY QUESTIONS
1. (a) Give the performance specification of Reflex klystron.
[L1][CO.3][4M]
(b) Define and explain current modulation with neat diagrams and required expressions.
[L1,L4][CO.3][4M]
2. (a) 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.
[L1,L4][CO.3][5M]
3
(b) Derive the expressions for bunched beam current and efficiency.
[L4][CO.3][5M]
(a) Write any two limitations of conventional tubes at Microwave frequencies.
[L1][CO.3][4M]
(b) With the help of velocity diagram explain principle of two-cavity Klystron amplifier.
[L4,L2][CO.3][6M]
4
Discuss in detail about Reflex Klystron and Calculate efficiency.
[L2,L4][CO.3][10M]
5
(a) List two discriminations between conventional tube and microwave tube. What can be the possible
Solutions to the limitations of conventional tubes at high frequencies? Which one is the best?
[L1][CO.3][5M]
(b) Write short notes on bunching process in a two-cavity klystron amplifier.
6
Explain the operation of a two cavity klystron amplifier. Derive expressions for bunched beam current
and efficiency.
7
[L1][CO.3][5M]
[L2,L4][CO.3][10M]
(a) Why at microwave frequency we talk of traveling waves with associated powers instead of
Voltages and currents?
[L1][CO.3][4M]
(b) What are slow wave structures? Explain how a helical TWT achieve amplification. [L2][CO.3][6M]
8
(a) What is a slow wave structure? Draw any four slow wave structures usable in a traveling wave
Tube.
[L1,L4][CO.3][4M]
(b) Explain the possibility of oscillations in a TWT amplifier. Suggest method to prevent oscillations.
[L2][CO.3][3M]
9
(c) Discuss about the differences between a TWT and a Klystron.
[L2][CO.3][3M]
(a) Write short notes on wave modes.
[L1][CO.3][4M]
(d) Mention how a TWT can be converted to an oscillator. Explain the operation of such a device.
Why large tuning range, are possible with such a device?
[L2][CO.3][6M]
10 (a) Derive the expressions for propagation constant and output power gain of TWT. [L4][CO.3][6M]
(b) In an O-type traveling wave tube, the acceleration voltage is 4000 V and the magnitude of the axial
electric field is 4 V/m. The phase velocity on the slow wave structure is 1.10 times the average
electron velocity. The operating frequency is 2 GHz. Determine the magnitude of velocity function.
.
[L4][CO.3][4M]
SIDDHARTH GROUP OF INSTITUTIONS :: PUTTUR
Siddharth Nagar, Narayanavanam Road – 517583
QUESTION BANK (OBJECTIVE)
Subject with Code : MWE (13A04603)
Year & Sem: III-B.Tech & II-Sem
Course & Branch: B.Tech - ECE
Regulation: R13
Unit-4
Cross-field tubes & Microwave Semiconductor devices
1. For 8 cavity magnetron-----no of modes will exists.
(a) 8
(b)
7
(c) 1
(b)45
(c)90
(b) Unfavoured
(c)Both A & B
(b) Spokes
(c) Both A & B
(b) 50-60%
(c) 15-35%
(b) 40-70%
(c) 15-35%
(b) Maximun
(c) Minimum
(b) Maximun
(c) Minimum
(c) Positive resistance
10. The example of negative resistance device is ----(a) IMPATT
(b) TRAPATT
(c) Gunn diode
(b) TRAPATT
(c) Gunn diode
(c) Gunn diode
(b) Active
(c) Both A & B
(b) Hall effect
(c) Both A & B
(b) Upper
]
[
]
[
]
(c) Both A & B
(d) None
[
]
[
]
[
]
[
]
[
]
[
]
(d)None
15. The mass of electron is maximum in ----- valley
(a) Lower
[
(d)None
14. Gunn effect depends on -----theory
(a) RWH
]
(d)None
13. Negative resistances devices are called ----- devices
(a) Passive
[
(d) None
12. The example of avalanche transit time device is ----(a) Tunnel diode (b) TRAPATT
]
(d) None
11. The example of TED is ----(a) IMPATT
[
(d) None
9. Solid state devices basically works on the principle of ----(a) Velocity modulation (b) Negative ressistance
]
(d) None
8. In magnetron at ρ=a,dρ/dt= ----(a) Zero
[
(d) 60-80%
7. In magnetron at ρ=a,dΦ/dt= ----(a) Zero
]
(d) 60-80%
6. The theoretical efficiency of Magnetron is ----(a) 5-20%
[
(d) None
5. The theoretical efficiency of TWT is ----(a) 5-20%
]
(d) None
4. The bunch of electrons in magnetron is known as ----(a) Electron clouds
[
(d)25
3. ----- electrons participating in energy transfer
(a) Favoured
]
(d) 3
2. For 8 cavity magnetron ,Φv= ----(a)0
[
(d)None
16. The mobility of electron is maximum in ----- valley
(a) Lower
(b) Upper
(c)
Both A & B
(b) Upper
(c)
Both A & B
(b) Upper
(c)
Both A & B
(b) Cu
(c) GaAs
(b) Hot
(c) Both A & B
(b) Non-linear reactance
(c) Controllable impedance
(b) ATTD
(c) Both A & B
]
[
]
[
]
(b) Coaxial Magnetron
[
]
[
]
(d) None
23. ----- uses an axial magnetic field and radial electric field.
(a) Reflex Klystron
[
(d) None
22. IMPATT is ----- device
(a) TED
]
(d) None
21. The parametric amplifier uses ----- for its amplification
(a) Resistance
[
(d) None
20. TEDs operate with ----- electrons
(a) Warm
]
(d) None
19. ----- substance is used for TEDs
(a) Al
[
(d) None
18. The mobility of electron is minimum in ----- valley
(a) Lower
]
(d) None
17. The mass of electron is minimum in ----- valley
(a) Lower
[
(c) Travelling wave magnetron
(d) CFA-Crossed Field Amplifier
24. The biggest advantage of the TRAPATT diode over the IMPATT diode is its
(a) Low noise
(b) Higher efficiency
(c) Ability to operate at higher frequencies
(d) Lesser sensitivity to harmonics
25. A varactor diode may not be useful at microwave frequencies
(a) For electronic tuning
(b) For frequency multiplication
(c) As an oscillator
(d) As a parametric amplifier
26. The negative resistance in a tunnel diode
[
]
[
]
[
]
[
]
(a) Is maximum at the peak point of the characteristic
(b) Is available between the peak and valley points
(c) Is maximum at valley point
(d) May be improved by the use of reverse bias
27. Which one of the following is a transferred electron device?
(a) BARITT diode
(b) IMPATT diode
(c) Gunn diode
(d) Step recovery diode
28. A PIN diode is suitable for use as a
(a) Microwave switch
[
(b) Microwave mixed diode (c) Microwave detector (d) None
29. The semiconductor diode which can be used in switching circuits at microwave range is[
(a) PIN diode
]
(b) Tunnel diode
(c) Varactor diode
]
(d) Gunn diode
30. In π mode operation of magnetron, the spokes due to phase focusing effect rotate
at an angular velocity corresponding to
(a) One pole/cycle
(b) Two poles/cycle
[
(c) Four poles/cycle
(d) Six poles/cycle
]
31. For Gunn diodes, gallium arsenide is preferred to silicon because the former
[
]
[
]
(a) Has a suitable empty energy band, which silicon does not have
(b) Has a higher ion mobility
(c) Has a lower noise at the highest frequencies
(d) Is capable of handling higher power densities
32. Travelling wave parametric amplifiers are used to
(a) Provide a greater gain
(b) Reduce the number of varactor diodes required
(c) Avoid the need for cooling
(d) Provide a greater bandwidth
33. The cavity magnetron use strapping to
[
]
[
]
[
]
36. One of the following microwave diode is suitable for very low power oscillator only [
]
(a) Prevent mode jumping
(b) Prevent cathode back heating
(c) Ensure bunching
(d) Improve the phase focusing
34. A magnetic field is used in the cavity magnetron to
(a) Prevent anode current in the absence of oscillations
(b) Ensure that the oscillations r pulsed
(c) Help in focusing the electron beam, thus preventing spreading
(d) Ensure that the electrons will orbit around the cathode
35. The biggest advantage of the trapatt diode over the impatt diode is it's
(a) Lower noise
(b) Higher efficiency
(c) Ability to operate at higher frequency
(d)Lesser sensitivity to harmonics
(a) Tunnel
(b) Avalanche
(c) Gunn
(d) Impatt
37. The transferred-electron bulk effect occurs in
(a) Germanium
(b) Gallium arsenide
[
(c) Silicon
]
(d) Metal semiconductor junctions
38. The tunnel diode
[
]
[
]
[
]
(a) Has a tiny hole through it's centre to facilitate tunnelling
(b) Is a point contact diode with a very high reverse resistance?
(c) Uses a high doping level to provide a narrow junction
(d) Works by quantum tunnelling exhibited by gallium arsenide only
39. A magnetron is used only as
(a) Amplifier
(b) Oscillator
(c) Mixer
(d) Frequency multiplier
40. Radar stands for
(a)Radio Distance and Ranging
(b) Radio Detection and Ranging
(c)Radio Direction and Ranging
(d) Radio Distance and Range
SHORT QUESTIONS
1. Why magnetron is called as cross filed device?
[L1][CO.4][2M]
2. What is π mode of operation?
[L1][CO.4][2M]
3. Give the Hull cutoff and Hartree conditions of Cylindrical Magnetron.
[L1][CO.4][2M]
4. List the type of circuit used for IMPATT diode circuits.
[L1][CO.4][2M]
5. What is negative resistance?
[L1][CO.4][2M]
6. Mention some applications of Gunn diode.
[L6][CO.4][2M]
7. What is Transferred electron effect?
[L1][CO.4][2M]
8. What is the parametric device?
[L1][CO.4][2M]
9. Write the applications of parametric amplifier.
[L6][CO.4][2M]
10. Write different microwave signal sources.
[L1][CO.4][2M]
11. What is the operating frequency of TRAPATT devices??
[L1][CO.4][2M]
12. Define GUNN EFFECT.
[L2][CO.4][2M]
13. What are the factors reducing efficiency of IMPATT diode?
[L1][CO.4][2M]
14. Can Gunn diodes can serve as microwave frequency generators?
[L1][CO.4][2M]
15. Compare Avalanche transit time devices.
[L3][CO.4][2M]
16. Leaving reflex klystron, what other devices are used as microwave signal sources?[L1][CO.4][2M]
17. What is the main advantage of TRAPATT over IMPATT?
[L1][CO.4][2M]
18. Why are FET’s preferred to bipolar transistor at high frequencies?
[L1][CO.4][2M]
19. List out the applications of Gunn and TRAPATT diodes.
[L6][CO.4][2M]
20. What are the Key phenomenon taking places in TRAPATT diode?
[L1][CO.4][2M]
ESSAY QUESTIONS
1. Explain the growth of oscillations in a travelling wave magnetron.
[L2][CO.4][10M]
2. Discuss in detail about cylindrical magnetron.
[L2][CO.4][10M]
3. (a) Explain the properties of high field domain for microwave generation and amplification. .
…
. .
[L2][CO.4][5M]
(b) Explain the rate of growth of space charge layers with the help of necessary expressions.
[L2,L4][CO.4][5M]
4. (a) What is transferred electron effect?
[L2][CO.4][4M]
(b) Explain clearly how a GUNN diode is different from a tunnel Diode Both A & B being a negative
resistance
devices.
[L2][CO.4][6M]
5. (a) What is parametric amplifier?
[L1][CO.4][4M]
(b) Explain it as an amplifier and frequency converter.
6. (a) Explain the V-I characteristics of a Gunn diode
(b) List the differences between microwave transistor and TED devices.
[L2][CO.4][6M]
[L2][CO.4][5M]
[L1][CO.4][5M]
7. (a) Give the classification of solid state microwave devices along with examples? [L1][CO.4][6M]
(b)
An n-type GaAs Gunn diode has following parameters:
Electron drift velocity: vd = 2.5 × 105 m/s.
Negative electron mobility: µn = 0.015 m2/ v. s.
Relative dielectric constant: €r = 13.1.
Determine the criterion for classifying the modes of operation
[L4][CO.4][4M]
8. Discuss how a decrease in drift velocity with increasing electric field can lead to the formation of a high
field domain for microwave generation and amplification.
[L2][CO.4][10M]
9. (a) Discuss in detail about Gunn diode modes of operation. [L2][CO.4][5M]
(b) What are bulk properties of a GUNN diode that give rise to negative resistance like characteristics?
.
[L1][CO.4][5M]
10. (a) Explain Two Valley Model Theory.
[L2][CO.4][6M]
(b) Write short notes on “TRAPATT diode”.
[L1][CO.4][4M]
SIDDHARTH GROUP OF INSTITUTIONS :: PUTTUR
Siddharth Nagar, Narayanavanam Road – 517583
QUESTION BANK (OBJECTIVE)
Subject with Code : MWE (13A04603)
Year & Sem: III-B.Tech & II-Sem
Course & Branch: B.Tech - ECE
Regulation: R13
Unit-5
Microwave Measurements
1. ----- is the device that generate mw power
(a) Magnetron
[
(b) TWT
(c) Reflex klystron
2. Low power can be measured by using ----- technique
(a) Bolometer
( b) Galvanometer
(c) Watt meter
3. Thermister is ----- device
(a) PTC
(c) Both A & B
4. In baratter the rate of resistance change is ----(a) 5Ω/mw
( b) 50Ω/mw
(b) Power
6. The attenuation can be measured by ----(a) Bolometer
(c) 60Ω/mw
(b) Power ratio
(c) Attenuation
technique
(c) Slotted line
(b) Inductive
(c) Resistive
8. The range of VSWR is ----(a) 0-1
(c) 1-10
9. Double minimum method can be used to measure ----(a) Impedance
(b) Attenuation
(c) High VSWR
]
(d) None
]
(d) None
]
(d) VSWR
[
]
(d) None
[
]
(d) None
[
(b) 1-∞
]
(d) None
[
7. In impedance measurement ,if vmin shifts left then impedance is ----(a) Capacitive
[
[
5. RF substitution method can be used to measure ----(a) Frequency
(d) None
[
(b) NTC
]
]
(d) None
[
(d) None
]
10. The quality factor QL= ----(a) 2/Δ
11.
(b) 1/Δ
(c) 1/2Δ
(b) Minimum
(c) Zero
(b) Slotted line
(c) Reflectometer
(b) VSWR
(c) Both A & B
(b) Attenuation
(c) Frequency
(b) Power ratio
(b) Transmits
(c) No action
(b) Pref*Pin
(c) Pref/Pin
(b) Peak power
(c) Instantaneous power
]
[
]
(c) Detector
[
]
[
]
[
]
(d) None
19. HEMT used in microwave circuit is a
(a) Source (b) High power amplifier
[
(d) None
18. Most of the power measuring microwave devices measure
(a) Average power
]
(d) None
17. Reflection coefficient ρ= ----(a) Pin/ Pref
[
(c) Double minimum method (d) None
16. In wave meter technique, the wave meter will ----- the power when fun=f0
(a) Absorbs
]
(d) None
15. High VSWR can measured by ----- technique
(a) Bolometer
[
(d) None
14. Magic tee can be used to measure -----(a) Impedance
]
(d) None
13. Reflectometer technique can be used to measure ----(a) Impedance
[
(d) None
12. Impedance can be measured using ----- technique
(a) Magic tee
]
(d) None
In wave meter technique, the output power is ----- when fun=f0
(a) Maximum
[
[
]
[
]
(d) Low noise Amplifier
20. In microwave power measurements using bolometer, the principle of working
is the variation of
(a) Inductance with absorption of power
(b) Resistance with absorption of power
(c) Capacitance with absorption of power
(d) Cavity dimensions with heat generated by the power
21. In Microwave we take the elements as
(a) Lumped circuit elements
[
(b) Distributed circuit elements
(c) Both A & B
(d) None
22. For handling large microwave power, the best medium is
(a) Coaxial line
(b) Rectangular waveguide
(c) Stripline
]
[
]
(d) Circular waveguide
23. Ionosphere preparation is not possible for microwaves because
[
]
[
]
[
]
(a) Microwaves will be fully absorbed by the ionospheric layers
(b) There will be an abrupt scattering in all directions
(c) Microwave will penetrate through the ionospheric layers
(d) There will be dispersion of microwave energy
24. A waveguide section in a microwave circuit will act as a
(a) Low-pass filter
(b) Band-pass filter
(c) High-pass filter
25. A varactor diode may not be useful at microwave frequencies
(a) For electronic tuning
(b) For frequency multiplication
(c) As an oscillator
(d) Parametric amplifier
(d) Band-reject filter
26. The negative resistance in a tunnel diode
[
]
[
]
(a) Is maximum at the peak point of the characteristic
(b) Is available between the peak and valley points
(c) Is maximum at valley point
(d) May be improved by the use of reverse bias
27. A PIN diode is suitable for use as a
(a) Microwave switch
(b) Microwave mixed diode (c) Microwave detector
28. Due to curvature of earth, microwave repeaters are placed at a distance of about
(a) 10 Km
(b) 50 Km
(c) 150 Km
(b) Large
(c) Small
(b) Flicker noise
(c) Thermal noise
(b) Ducting
(c) Wave tilt
(b) Flexible
(c) Coaxial
]
[
]
[
]
[
]
[
]
(d) Troposcatter
32. Indicate which of the following cannot be followed by the word waveguide
(a) Elliptical
[
(d) Transit time noise
31. The phenomenon of microwave signals following the curvature of earth is known as
(a) Faraday effect
]
(d) Very Small
30. Which of the following noise becomes important at microwave frequencies
(a) Shot noise
[
(d) 250 Km
29. At microwave frequencies the size of the antenna becomes
(a) Very large
(d) None
(d) Ridged
33. For low attenuation best transmission medium is
(a) Flexible waveguide (b) Ridged waveguide (c) Rectangular waveguide (d) Coaxial line
34. The glass tube of a TWT may be coated with aquadag to
(a) Help focusing
(b) Provide attenuation
[
(c) Improve bunching (d) Increase gain
35. One of the following is not used as a microwave mixer or detector
(a) Crystal diode
(b) Schottky barrier diode
]
(c) Backward diode
[
]
[
]
[
]
(d) Pin diode
36. The tunnel diode
(a) Has a tiny hole through it's center to facilitate tunneling
(b) Is a point contact diode with a very high reverse resistance
(c) Uses a high doping level to provide a narrow junction
(d) Works by quantum tunnelling exhibited by gallium arsenide only
37. A tunnel diode is loosely coupled to it's cavity in order to
(a) Increase the frequency stability
(b) Increase the available -ve resistance
(c) Faciliting tuning
(d) Allow operation at the high frequency
38. --- is a object detection system that uses microwaves
(a) Microwave oven (b) Transmitter
(c) Radar
39. ---- is an electronically controlled home appliance used for cooking
(a) Radar
(b) Microwave oven
(c) Satellite
40. Speed of em wave in free space is -----(a) 3 x 1010m/s
(b) 3 x 1012cm/s
[
(d) Satellite
[
]
(d) None
[
(c) 3 x 1010cm/s
]
(d) None
]
SHORT QUESTIONS
1. Define VSWR and Reflection coefficient.
[L1][CO.5][2M]
2. Draw the block diagram of microwave bench.
[L4][CO.5][2M]
3. What do you mean by slotted line?
[L1][CO.5][2M]
4. What is Bolometer and calorimeter?
[L1][CO.5][2M]
5. What is a VSWR meter?
[L1][CO.5][2M]
6. Distinguish between low frequency measurements and microwave measurements. [L4][CO.5][2M]
7. Distinguish between thermistor and barrette?
[L4][CO.5][2M]
8. What are the precautions taken while measuring microwave measurements?
[L1][CO.5][2M]
9. What are the methods measuring attenuation and Impedance.
[L1][CO.5][2M]
10. What is spectrum analyzer and list different spectrum analyzer’s.
[L1][CO.5][2M]
11. Distinguish between the terms: Insertion Loss and Attenuation.
[L4][CO.5][2M]
12. How are microwave measurements different from low frequency measurements? [L1][CO.5][2M]
13. Describe use of dc ammeter at microwave frequencies.
[L1][CO.5][2M]
14. Write short notes on usage of Isolator and its significance in a microwave bench. [L1][CO.5][2M]
15. List some application of spectrum analyzer.
[L6][CO.5][2M]
16. How do you measure microwave frequency?
[L1][CO.5][2M]
17. List the types of spectrum analyze.
[L1][CO.5][2M]
18. Define the term Q factor for a cavity and Tunable Probe.
[L1][CO.5][2M]
19. Two identical 30dB directional couplers are used to sample incident and reflected power in a wave
guide, VSWR=2 and the output of the coupler sampling incident power=4.5mW.What is the value of
reflected power.
[L4][CO.5][2M]
20. What is network analyzer?
[L1][CO.5][2M]
ESSAY QUESTIONS
1. (a) Distinguish between low frequency measurement and microwave measurements. [L4][CO.5][4M]
(b) With the help of a neat sketch, briefly explain the functions of different blocks of a microwave
bench.
2. (a)
Discuss
[L2][CO.5][6M]
about
the
important
considerations
when
making
attenuation
measurement.
[L1][CO.5][5M]
(b) Explain about measurement of attenuation using a microwave bench setup. [L2][CO.5][5M]
3. (a) Discuss in detail about measurement of VSWR.
[L2][CO.5][6M]
(b) Determine s-parameters of a 10 dB directional coupler of directional coupler of Directivity 30
dB. Assuming directivity of coupler loss-less VSWR at each port under Matched condition is unity.
.
[L4][CO.5][4M]
4. (a) What is spectrum analyzer? List the types of spectrum analyzer. List some application of Spectrum
analyzer.
(b) Describe a microwave bench.
5. (a) How to measure an attenuation of a given microwave signal?
[L1,L6][CO.5][6M]
[L4][CO.5][4M]
[L2][CO.5][4M]
(b) What is VSWR? Explain the method measurement for low and high VSWR?. [L2][CO.5][6M]
6. (a) Distinguish between the terms: Insertion Loss and Attenuation. With a neat set up, describe the
method of measurement of attenuation using a waveguide bench.
[L4][CO.5][6M]
(b) Write short notes on usage of Isolator and its significance in a microwave bench. [L1][CO.5][4M]
7. (a) Write a short note on power ratio method.
[L1][CO.5][5M]
(b) Write short notes on RF substitution method.
[L1][CO.5][5M]
8. (a) Two identical directional couplers are placed in a waveguide to sample the incident and the reflected
power. The meter readings show that the power level of the reverse coupler is 10dB down from the
level of the forward coupler. What is the value of the SWR on the waveguide?
[L4][CO.5][4M]
(b) How are microwave measurements different from low frequency measurements? [L1][CO.5][6M]
9. (a) Draw the experimental setup necessary for the measurement of impedance using slotted line.
Explain in detail.
(b) What are the characteristics of detectors used in microwave measurements?
10 (a) Discuss in detail about measurement of attenuation.
[L4,L2][CO.5][5M]
[L1][CO.5][5M]
[L2][CO.5][4M]
(b) Write short notes on “Reflection co-efficient and Insertion loss measurement at microwave
frequencies”.
[L1][CO.5][6M]