1 (a)
What are the applications of Microwaves?

5 M

1 (b)
Can TEM mode exist in hollow waveguide? Justify your answer.

5 M

1 (c)
What are O-type and M-type devices in microwave?

5 M

1 (d)
Explain the terms: Cut-off frequency, Dominant mode, Phase velocity, Group velocity.

5 M

2 (a)
Derive wave equation for TE wave and obtain all the field components in a rectangular waveguide.

10 M

2 (b)
Explain the action of isolator and circulator using ferrites, mention their typical applications.

10 M

3 (a)
Draw a neat diagram of two cavity Klystron amplifier and explain the bunching process. Derive the equation of velocity modulation.

10 M

3 (b)
An X-band pulsed cylindrical magnetron has the following parameters:

Anode voltage: Vo = 2.6x10

Beam current: Io=27A

Flux density: Bo=0.336Wb/m

Radius of cathode cylinder: a=5 cm

Radius of vane edge to centre: b=10 cm

Compute the cyclotron angular frequency

the cut off voltage for a fixed B and

the cut off magnetic flux density for a fixed Vo.

Anode voltage: Vo = 2.6x10

^{4}VBeam current: Io=27A

Flux density: Bo=0.336Wb/m

^{2}Radius of cathode cylinder: a=5 cm

Radius of vane edge to centre: b=10 cm

Compute the cyclotron angular frequency

the cut off voltage for a fixed B and

the cut off magnetic flux density for a fixed Vo.

10 M

4 (a)
Draw and explain two-hole directional coupler. Define coupling factor, directivity and isolation. Derive S matrix for the same.

10 M

4 (b)
Explain Gunn Effect with the two valley model of Gunn diode. What are the criteria that a semiconductor must satisfy in order to exhibit negative resistance?

10 M

5 (a)
What are slow wave structures? Explain how helical TWT does amplification.

10 M

5 (b)
Describe the types of strip lines in brief.

5 M

5 (c)
Explain the excitation of modes in circular waveguides.

5 M

6 (a)
Explain the methods used for power measurement in microwaves.

10 M

6 (b)
With the help of sketch distinguish between IMPATT and TRAPATT diode.

10 M

Write short notes on any

**three**:-
7 (a)
Limitations of conventional tubes at microwave frequencies.

7 M

7 (b)
Waveguide attenuators.

7 M

7 (c)
Measurement of VSWR.

7 M

7 (d)
Microwave transistors.

7 M

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