1 (a)
Describe the importance of the 'S' parameters in microwave.

5 M

1 (b)
Write applications of 'Microwaves'.

5 M

1 (c)
Compare 'Travelling Wave Tube' with 'Klystron'.

5 M

1 (d)
How are waveguides different from the normal two wire transmission lines? Discuss the similarities and dissimilarities.

5 M

2 (a)
Justify: 'TEM mode does not exist in hollow waveguide'.

5 M

2 (b)
Starting with Maxwell's equations, derive the expression of TE

_{mm}wave in rectangular waveguide.
10 M

2 (c)
What are 'O' and 'M' types of tubes in the microwaves.

5 M

3 (a)
Draw a neat diagram of Two Cavity Klystron Amplifier. Explain with diagram, its bunching process. Derive the equation of its velocity modulation.

10 M

3 (b)
Explain the working of 'Gyrator' with its neat diagram.

5 M

3 (c)
An air-filled circular waveguide with radius of 5 cm, operating at TE

i) Determine the cut-off frequency

ii) Determine the guide wavelength for the operating frequency of 3 Ghz.

iii) Determine the wave impedance in the guide.

_{11}mode,i) Determine the cut-off frequency

ii) Determine the guide wavelength for the operating frequency of 3 Ghz.

iii) Determine the wave impedance in the guide.

5 M

4 (a)
Draw and explain 'Two-Hole Directional Coupler'.

Define:

i) Coupling Factor

ii) Directivity

iii) Isolation

Also, Derive the S-Matrix for the same.

Define:

i) Coupling Factor

ii) Directivity

iii) Isolation

Also, Derive the S-Matrix for the same.

10 M

4 (b)
Why 'Hybrid Tee' is called as 'Magic Tee'. Derive S-Matrix for EH plane Tee.

5 M

4 (c)
Explain with neat diagram, working of 'Microwave Transistor'.

5 M

5 (a)
Explain the set up for VSWR measurement in microwaves.

10 M

5 (b)
Justify: Wavelength is a High Pass Filter'.

5 M

5 (c)
A Reflex Klystron Operates under the following conditions:

V

ii) R

The tube is oscillating at 'f

i) Find the value of repeller voltage.

ii) Find the direct current necessary to give a microwave gap voltage of 200 Volts.

iii) What is the electronic efficiency under this conditions.

V

_{o}=600 V, L=1mmii) R

_{sh}=15 KΩ, f_{r}=9 GhzThe tube is oscillating at 'f

_{r}' at the peak of the n=2 mode. Assume that the transit time through the gap and beam loading can be neglected.i) Find the value of repeller voltage.

ii) Find the direct current necessary to give a microwave gap voltage of 200 Volts.

iii) What is the electronic efficiency under this conditions.

5 M

6 (a)
Explain with neat diagram, principle of working of 'Rectangular Cavity Resonator'. Also obtain the expression for its resonance frequency.

10 M

6 (b)
Explain following terms:-

i) Cut -off frequency

ii) Dominant Mode

iii) Phase Velocity

iv) Group Velocity

v) Degenerate Mode.

i) Cut -off frequency

ii) Dominant Mode

iii) Phase Velocity

iv) Group Velocity

v) Degenerate Mode.

5 M

6 (c)
An IMPATT diode has following parameters carrier drift velocity v

Drift region length L=6μm.

Maximum operating voltage V

Maximum operating current I

Efficiency Kη=15%

Breakdown voltage V

Find:

i) The maximum power in watt.

ii) The resonant frequency.

_{d}=2×10^{7}cm/s.Drift region length L=6μm.

Maximum operating voltage V

_{Omax}=100 VoltsMaximum operating current I

_{Omax}=200 mAmp.Efficiency Kη=15%

Breakdown voltage V

_{bd}=90 Volt.Find:

i) The maximum power in watt.

ii) The resonant frequency.

5 M

Write short notes on any four of the following:

7 (a)
Two Valley Model Theory

5 M

7 (b)
Strip Lines

5 M

7 (c)
Apple-gate Diagram of Reflex Klystron

5 M

7 (d)
Slow wave structures

5 M

7 (e)
Limitations of conventional vacuum tubes at microwave frequency.

5 M

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