Download GTU BE/B.Tech 2018 Winter 7th Sem Old 171001 Microwave Engineering Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER-VII (OLD) EXAMINATION — WINTER 2018

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Subject Code: 171001 Date: 06/12/2018
Subject Name: Microwave Engineering
Time: 10:30 AM TO 01:00 PM Total Marks: 70

Instructions:

1. Attempt all questions.

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2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

Q.1 (a) Define following : (i) Guide wave length (ii) Transmission coefficient (iii) Phase 07
velocity (iv) Gunn effect (v) VSWR (vi) Return loss (vii) Characteristic impedance
(b) Describe the problems associated with conventional tubes at UHF and Microwave? 07

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Q.2 (a) Explain reflection coefficient of transmission line and standing wave. Derive expression 07
for impedance and reflection coefficient at any point on the line.
(b) A lossless line has a characteristic impedance of 50 O and is terminated in a load 07
resistance of 75 O. The line is energized by a generator which has an output impedance
of 50 O and an open-circuit output voltage of 30 V (rms). The line is assumed to be 2.25

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wavelengths long.
Determine: a. The input impedance
b. The magnitude of the instantaneous load voltage
c. The instantaneous power delivered to the load

OR

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(b) Explain TE, TM and TEM modes in a waveguide. What is meant by the Dominant mode 07
in a rectangular waveguide? Explain why TEM mode can’t propagate through a
rectangular waveguide.

Q.3 (a) List different types of Magnetron. Explain mechanism of oscillations of Magnetron 07
Oscillator with diagram.

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(b) Explain working of two cavity klystron with necessary diagram and waveforms. 07

OR

Q.3 (a) Explain the construction and working of IMPATT diode. What are its applications? 07
(b) With the aid of Diagram, explain the operation of “Two Hole Directional Coupler” 07

Q.4 (a) Write properties of smith chart and explain its application with any one example. 07

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(b) Explain in detail E-plane Tee. With S-matrix prove that the Tee junction cannot be 07
matched to all the three arms simultaneously.

OR

Q.4 (a) What is microstrip line? Derive equation of characteristic impedance and quality factor 07
of microstrip line:

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(b) Explain different display methods of RADAR. 07

Q.5 (a) Explain the principle of MTI radar with block diagram. 07
(b) Define Microwave. Write advantage, disadvantage and industrial application of 07
microwave.

OR

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Q.5 (a) Write short note on Circulators and isolators 07
(b) Write a note on any one of the following. 07
(1) Step Recovery Diode and its applications. (2) ?/4 Line and its applications.

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