G1025 Pages: 2

Reg No.:_ Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
SEVENTH SEMESTER B.TECH DEGREE EXAMINATION(S), MAY 2019

Course Code: EC403
Course Name: MICROWAVE & RADAR ENGINEERING

Max. Marks: 100 Duration:

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PARTA

Answer any two full questions, each carries 15 marks.
Explain the significance of re-entrant cavities in microwave tubes. What are the
different types of re-entrant cavities?
With the help of a schematic structural diagram explain the working of a two
cavity Klystron Amplifier. Also give its typical specifications.
How oscillation generate in reflex klystron?
With the help of applegate diagram describe the bunching process of two cavity
klystron amplifier and derive the bunching parameter also.

A reflex Klystron operates under following Conditions:
Vo=600V, Length L=lmm, ശം =15KQ, e/m =1.759x1011, f. =9GHz

The tube is oscillating ೩! { at the peak of the n= 2 mode or न mode.

Assume that the transit time through the gap and beam loading can be
neglected.
a) Find the value of the repeller voltage Vp
b) Find the direct current necessary to give a microwave gap voltage of
200V

c)What is the electronic efficiency under this condition?

Define Velocity modulation and how velocity modulation changes to current
density modulation in Klystron Amplifier:-
PART ‏تا‎

Answer any two full questions, each carries 15 marks.
What are different types of waves generated in a TWT after interaction with
electron beam and RF signal:-.
A travelling wave tube (TWT) operates under the following parameters: Beam
voltage, Vo=3kV; Beam current, 10530൩2൧; Characteristics of helix,Zo=10Q;
Circuit length, N=50; Frequency, f=10GHz. Determine: (೩) the gain parameter,
C (b) the output power gain, Ap in decibels and (c) all four propagation
constants.

Draw the block diagram of a typical microwave bench setup and label all the

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