Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 6th Semester (Sixth Semester) 2015-2016 EEC 603NEC 601 Microwave Engineering Question Paper
(Following Paper ID and Roll No. to be ?lled in your Answer Books)
Roll No.
?B.TECH.
Theory Examination (Semester-VI) 2015-16
MICROWAVE ENGINEERING
T ime : 3 Hours Max. Marks : 100
SECTION-A
1. Attempt all questions. (2 x 10:20)
a] Differentiate dominant and degenerative Mode in waveguide.
b) Calculate the lowest resonant frequency of a rectangular resonator of dimension a=2 cm, b=1 cm, cl: 3
cm.
c) Why the low frequency parameters cannot be measured in Microwaves?
d) What parameters determine the performance of directional coupler?
e) How the limitation of conventional tubes at microwave frequency can be overcome?
f] What is strapping in Magnetron? .
g] Why the S-parameters but not the H,Y and 2 parameters are used in microwaves?
h) What do you meant by slotted line?
i) Define the purpose of slow wave structures used in TWT ampli?ers.
i] State the conditions for an IMPATT diode to produce oscillations.
SECTION- B
2. Attempt any three questions. [10 x 5:50)
a) How are waveguides different from normal two wire transmission line. Discuss the similarities and
dissimilarities. Show that for a TEm mode, a frequency of 6 6112 will pass through the waveguide of
dimension 3 = 1.5 cm, b = 1cm ifa dielectric with Er: 4- is inserted into the waveguide.
b] Describe the operation of a two hole directional coupler.
A 90 W power source is connected to the input ofa directional coupler with C = 20 dB, D = 35 dB and an
insertion loss of 0.5 dB. Find the output powers at the through, coupled and isolated ports. Assume all
ports to be matched.
6] Explain the concept of negative differential conductivity. Explain the different modes of oscillation of
Gunn diode.
d) What are various methods for measuring frequency? Discuss them in detail.
9) Write a Schematic diagram of re?ex klystron. Explain the action of the tube giving importance to
Applegate diagram.
0 Explain how a tunnel diode can be used as an ampli?er and as an oscillator with the necessary circuit
diagram
g) Explain the operation of a Faraday rotation isolator with the help of neat sketch. List the applications of
Ferrite isolator
h) Explain the following:
(i) Phase Shifters
[ii] Wave guide discontinuities
SECTION- C
Attempt any two questions. (15 x 2:30]
3. Attempt the following
a) What are slow wave structures? Explain how a helical TW'I? achieves ampli?cation?
b) Derive the Hull cut off voltage equation in Cylindrical Magnetron. Explain the frequency pulling and
pushing effect.
4. Attempt the following
a) Explain the operation of microwave transistors giving an emphasis on their performance parameters.
b) With the help of suitable diagram, Explain the general setup ofMicrowave test bench.
5. Attempt the following
a) A Magic-T is terminated at collinear ports 1 and 2 and difference port 4 by impedance of re?ection
coef?cient 05, 0.6 and 0.8 respectively. If the 1 W power is fed at the sum port 3, Caculate the power
re?ected at the port 3 and power transmitted to the other three ports.
b) What are avalanche transit time devices? Explain the operation. construction and application of the
TRAPT'I?.
This post was last modified on 29 January 2020