Solve any one question from Q1 and Q2

1 (a)
The TE

_{10}mode is propagated in a rectangular waveguide of dimensions a = 6cm and b = 4 cm, by means of a travelling detector. The distance between a maximum and minimum is found to be 4.55 cm. Find the frequency of the wave.
7 M

1 (b)
State different types of stripline and distinguish between Stripline and
Microstrip line in detail.

7 M

1 (c)
What is the significance of scattering matrix? Write the properties of
S-matrix.

6 M

2 (a)
Explain the terms with respect to waveguide:

i) Dominant Mode.

ii) Cut-off Frequency.

iii) Guide Wavelength.

i) Dominant Mode.

ii) Cut-off Frequency.

iii) Guide Wavelength.

7 M

2 (b)
Explain any two applications of circulator.

7 M

2 (c)
The collinear ports 1 and 2 of a Magic Tee are terminated by impedances
of reflection coefficients ρ

_{1}=0.5 and ρ_{2}=0.6. The difference port 4 is terminated by an impedance with reflection coefficient of 0.8. If 1W power is fed at sum port 3, calculate the power reflected at port 3 and the power divisions at the other ports.
6 M

Solve any one question from Q3 and Q4

3 (a)
What are the limitations of conventional tubes at microwave frequencies
and how to overcome these limitations?

9 M

3 (b)
How the oscillations are sustained in Cavity Magnetron? Explain the
process of phase focusing effect.

9 M

4 (a)
Explain the operation of Travelling Wave Tube with its slow wave
Structure.

9 M

4 (b)
A two cavity Klystron amplifier has the following specifications:

Beam Voltage : V

Beam Current : I

Frequency : f = 8GHz

Gap spacing in either cavity : d = 1mm

Spacing between centers of cavities : L = 4cm

Effective shunt impedance : R

Determine:

i) The electron velocity.

ii) The dc transit time of electron.

iii) The input voltage for maximum output voltage.

iv) The voltage gain in decibels.

Beam Voltage : V

_{0}= 900 VBeam Current : I

_{0}= 30 mAFrequency : f = 8GHz

Gap spacing in either cavity : d = 1mm

Spacing between centers of cavities : L = 4cm

Effective shunt impedance : R

_{sh}: 40kΩDetermine:

i) The electron velocity.

ii) The dc transit time of electron.

iii) The input voltage for maximum output voltage.

iv) The voltage gain in decibels.

9 M

Solve any one question from Q5 and Q6

5 (a)
Draw equivalent circuit of Varactor diode. Explain in detail its construction and operation.

8 M

5 (b)
Explain principle of operation, IV characteristics and equivalent circuit of microwave Tunnel diode.

8 M

6 (a)
Explain Gunn effect using two valley model. Mention its typical characteristic and applications of Gunn diode.

8 M

6 (b)
With suitable expression explain power frequency limitations of microwave transistor.

4 M

6 (c)
In a Gunn diode with active length 20&mulm, the drift velocity of electrons is 2*10

^{7}cm/s. Calculate natural frequency of the diode and its critical Voltage.
4 M

Solve any one question from Q7 and Q8

7 (a)
Explain any two methods of measuring impedance of a terminating load in a microwave system.

8 M

7 (b)
Enlist methods of measuring the Q of a cavity resonator. Explain any one method in detail.

8 M

8 (a)
Explain with neat block diagram power measurement of microwave generator using

i) Bolometer.

ii) Calorimeter.

i) Bolometer.

ii) Calorimeter.

8 M

8 (b)
Describe in detail the techniques used for VSWR measurement.

8 M

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