M.Sc. (Semester III) (CBCS) Examination Nov/Dec-2018
Electronic Science
MICROWAVE ELECTRONICS AND APPLICATIONS
Time: 2½ Hours Max. Marks: 70
Instructions: All questions are compulsory.
Figures to the right indicate full marks.
Q.1 Select the most correct alternative 14
According to IEEE microwave frequency band the range of C is
4-8GHz 1-2 GHz
2-4 GHz 8-12 GHz
The Z0 of rectangular waveguide is
50 ohm 75 ohm
100 ohm 300 ohm
The two cavity klystron operates on principal of
Velocity modulation Current modulation
Velocity Current Modulation None of these
A micro-strip line is also called as
Open strip line Closed strip line
Mismatch line Matched line
In Gunn diode, the current density decreases with increase in dielectric
field is called as
-ve differential resistivity +ve differential resistivity
differential conductivity None of these
In Smith chart, upper half of the chart is indicated as inductive reactance
and lower half is indicated as capacitive and is also represented as
jx jx, -jx
jx, jx None of these
Gunn diode is made up of
SiO2 GaAs
GaP GaAIS
TE11 as is dominant mode of propagation in
Rectangular waveguide Circular waveguide
Square waveguide Coaxial line
In microwave for high power application which oscillator is used?
TWT Gunn diode
Reflex Klystron Klystron
10) Sinusoidal FM-CW RADAR is used where is required.
range both range and velocity
velocity none of these
11) E plane TEE is also called as a TEE.
Series Shunt
Parallel Magic
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SLR-VH-242
12) Which of the following is Avalanche Transit time device?
BARITT TRAPATT
IMPATT All of these
13) What will Phase velocity (rectangular waveguide), when frequency is
equal to critical frequency?
Zero Indefinite
Infinite Lower
14) Magnetron is a/an
amplifier oscillator
transponder all of these
Q.2 Answer any four of the following. 08
Define Poynting's energy theorem.
Define microwave cavities along with their types.
Which are the high frequency limitation of conventional tubes?
Short note on HEMT.
Discuss one of the industrial application of microwave.
Answer any two of the following. 06
Impedance matching
H-tee with their characteristic
Effect of microwave radiation on human body
Q.3 Answer any two of the following. 08
Explain standing wave ratio and it's relation with reflection coefficient.
What is excitation of modes in waveguides?
What is CW-Doppler RADAR?
Answer any one of the following. 06
Discuss Maxwell's equation with their relevant definition.
Explain the construction and working of Two Cavity Klystron.
Q.4 Answer any two of the following. 10
Discuss what is Smith chart along with its characteristic.
Explain the construction and operation principle of Cylindrical
Magnetron.
Explain Magic tee in brief.
Answer any one of the following. 04
A load of ZL 100 j50 Ω terminates with 50 Ω line, what are the load
admittance and the input admittance if the line is 0.15 long?
A transmission line has L=0.2 C=300 R
G=0.01 S/m. Find
Propagation Const
ii) Z0 at 500 MHz
Q.5 Answer any two of the following. 14
Explain the TM modes of rectangular waveguides with cut-off frequency,
cut-off wave number, characteristic wave impedance of TMmn in
waveguide.
Explain the TRAPATT diode with its principle of operation.
Distinguish between modulated and un-modulated CW RADAR.