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Reg No.:_. Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

SEVENTH SEMESTER B.TECH DEGREE EXAMINATION(R&S), DECEMBER 2019

Max. Marks: 100

0)
2 a)
b)
3 a)
b)

Course Code: EC403
Course Name: MICROWAVE & RADAR ENGINEERING

PARTA

Answer any two full questions, each carries 15 marks.
Derive the resonant frequency of a rectangular cavity resonator.
Determine the resonant frequency of an air filled rectangular cavity operating in
the dominant mode with dimensions ೩5 a=4cm, b=5cm and d=6cm.
Assuming pi mode of oscillations explain how a magnetron can sustain its
oscillations using the cross field.
With the help of Applegate diagram describe the bunching process in a two
cavity klystron amplifier and derive the bunching parameter.
A reflex klystron operates under the following conditions:
V.=500V, 1२५ =10KQ, {= 8 GHz, L >1 mm, e/m = 1.759 x 10'' (MKS system)

The tube is oscillating at 1. at the peak of the n = 2 or 1= mode. Assume that the

transit time through the gap and beam loading to be neglected. Determine:-
1. The value of the repeller voltage Vr.
2. The direct current necessary to give a microwave gap voltage of 200 V.
3. The electronic efficiency under this condition.
Explain the electronic admittance of the gap in the case of reflex klystron. With
admittance diagram explain the condition required for oscillation in a reflex
Klystron.
Given the parameters of a two cavity klystron amplifier:
Beam Voltage = 100017
Beam current = 50mA,
Operating frequency = 10GHz
Gap 50೩01181110,
Spacing between two cavities = 5cm,
Ro= 40KQ, Rs = 30KQ
Determine:
1. Input signal to generate maximum output voltage.
2. Voltage gain.
3. Efficiency.

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Duration: 3 Hours

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