M.Sc. (Semester IV) (CBCS) Examination Mar/Apr-2018
Physics (Applied Electronics)
MICROWAVE DEVICES CIRCUITS
Time: 2½ Hours
Max. Marks: 70
Instructions: Q. and are compulsory. Answer any three questions from Q.3 to Q.7. All questions carry equal marks.
Q.1

Select the most correct alternative.
06
According to IEEE, the microwave frequency range of Ku-band is
4 to 8 GHz
8 to 12 GHz
12 to 18 GHz
18 to 26 GHz
The following waves do not exist in waveguides
TM waves
TEM waves
TE waves
TE and TM waves
The periodic fluctuations of current passing through the n-type GaAs was discovered by
J. B. Gunn
R. C. Johnson
B. C. DeLoach
B. G. Cohen
The two cavity Klystron is operated on the principle of
velocity modulation
velocity and current modulation
current modulation
none of the above
A microstripline is also called as
open-strip line
closed-strip line
mismatch line
none of the above
The characteristic impedance of a rectangular waveguide is
50 Ohms
75 Ohms
100 Ohms
300 Ohms

State true or false:
08
The electric and magnetic wave equations are derived from Maxwell's equations.
The wave in the TWT is a propagating wave.
The Gunn diode is always operated in the negative resistance region.
A line terminated in its characteristic impedance has a standing wave ratio of unity.
The impedance matching is very desirable in transmission line.
The passive elements used to control the amount of microwave power in a transmission line are called as attenuators.
The EM wave inside a waveguide can have an infinite number of patterns called modes.
In wave polarization, the orientation of electric field changes.
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SLR-UR-581
Q.2
Write short notes.
14
Maxwell's Equations
05
Gunn effect
05
Waveguide attenuators
04
Q.3
Derive the wave equations with the help of Maxwell's equations.
10
Give an account on boundary conditions.
04
Q.4
Derive the equations transmission coefficient and reflection coefficient.
08
Derive an expression for velocity modulation in klystron.
06
Q.5
Discuss in detail, the various coaxial and stripline components.
10
Give an account on impedance matching.
04
Q.6
Derive equations for losses in coaxial lines.
10
Write note on standing wave ratio.
04
Q.7
With a neat sketch, explain the construction and working of phase shifters.
08
Write a note on wave propagation in perfect insulators.
06