Download AKTU B-Tech 6th Sem 2014-2015 Microwave Engineering Question Paper

Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 6th Semester (Sixth Semester) 2014-2015 Microwave Engineering Question Paper

Printed Pages : 4
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(Following Paper 1]) and Roll No. to be ?lled in your Answer Book)
PAPER ID : 131603
Roll No.
B. Tech.
? (SEM. VI) THEORY EXAMINATION, 2014-15
MICROWAVE ENGINEERING
Time : 3 Hours] 1 [Total Marks :?100
Note :
Attempt all the questions.
Each question carries equal marks.
1 Attempt any four parts of the following 25><4=20
(a) .
(b)
(C)
(d)
131603]
What are waveguides ? Explain the following
terms :
(i) Phase velocity
(ii) Group velocity
(iii) Cut-o?' wavelength.
Derive the ?eld distribution of TE 10 mode in
rectangular waveguide and draw its ?eld
pattern.
Show that TEOl and TMIO modes do not exist
in rectangular wave guide.
What is microstrip line ? How does its
characteristic impedance change with change
in width to height ratio.
1 [ Contd...

(e) A rectangular wave guide has a cross sectional
area 2.29 cm X 1.45 cm and the operating
frequency is 9.0 GHz. Calculate the value of
(a) free space wavelength, (b) cut o?? frequency,
(0) cut off wave length.
(1) De?ne quality factor of a cavity resonator.
Derive expression for quality factor Q of a
rectangular cavity resonator.
Attempt any four parts of the following: 5x4=20
(a) What do you mean by microwave passive
devices ? Describe E-plane tee, H-plane tee
and Magic tee.
(b) What are S-parameters ? Why are they used
at microwave frequencies to describe multiport
network ?
(c)v Describe rotary-vane attenuator. Show that
its [S] matrix is given by
[s1= m ?329]
(d) What is a phase shifter ? Describe a rotary
. phase shifter and explain its principle.
(e) Show that the scattering matrix of four port
circular using magic tees is
[s1=
OOHO
OHOO
HOOO
000?-
131603] 2 [ Contd...
(1) With support of ?gures explain the working
of an isolator.
Attempt any two parts of the 10x2=20
following :
(a) A two cavity klystron ampli?er has the
following speci?cations : Beam voltage = 900 V,
Beam current = 30 mA, frequency = 8GHz,
gap spacing in either cavity = 1 mm, spacing
between centers of cavities = 4cm and effective
shunt impedance = 49 kg. Determine
(i) Electron velocity ,
(ii) D.C. transit time of electron
(iii) Input voltage for maximum output
voltage
(iv) Voltage gain ?in dB
(b) By means of an appropriate diagram explain
the operation of a re?ex klystron. Calculate
the modulated velocity of electron if the
electron enters the cavity at the instant when
the R. F. signal is at its negative peak. Assume
cavity gap to be 2mm and the frequency of
' RF. signal to be 9 GHz with peak to peak
value of 10 mV and Va =1000 V.
(c) With support of ?gure explain the working of
TWT.
Attempt any two parts of the . 10X2=20
following :
(a) Give the construction of tunnel diode. Explain
its' voltx-ampere characteristics.
131603] 3 [ Contd...

(b)
Explain the construction, fabrication 'and
domain formation of Gunn diode.
(c) Explain IMPA?I?T and TRAPAT'I? diodes and
compare their performance.
5 Attempt any two parts of the 10XZ=20
following i
(a) Explain :
(b)
(e)
I 131603]
(i) Thermocouple detector
(ii) Bolometer mount technique
(iii) Calorimeter wattmeter technique
(iv) Slotted line carriage and its importance
. in yW test bench.
Discuss the salient features of microwave
measurements. Describe a voltage standing ?
wave ratio (VSWR) meter. .
What do you mean by insertion loss and
attenuation ? Discuss any one method for
measurement of attenuation using ,u wave
test bench.
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