Microwave Engineering Question Paper - Dec 16 - Electronics And Communication Engineering (Semester 7) - Jawaharlal Nehru Technological University (JNTUH)

4views

written 4.9 years ago by

teamques10 ★ 64k

Microwave Engineering - Dec 16

Electronics And Communication Engineering (Semester 7)

Total marks: 75
Total time: 3 Hours

Note:-

This question paper contains two parts A and B.

Part A is compulsory which carries 25 marks.

Part B consists of 5 units. Answer any one full question form each unit.

Each question carries 10 marks and may have a,b,c as sub questions.

Part -A

1.a. Calculate the group and phase velocity fir an angle of incidence of 33°.

(2 marks) 00

1.b Explain how the excitation of mode is done in rectangular waveguide.

(3 marks) 00

1.c. What is Q factor?

(2 marks) 00

1.d. Write short notes on Waveguide Irises.

(3 marks) 00

1.e. What are the limitations of conventional vacuum tubes at microwave frequencies.

(2marks) 00

1.f. What is the principles of a working of backward wave oscillator.

(3 marks) 00

1.g What are the disadvantage of strapping?

(3 marks) 00

1.h. A magnetron has a cathode radius of 2.5mm and anode radius of 5 mm. What is the cut-off potential if a 0.27 wb/m² magnetic field is applied?

(3 marks) 00

1.i. What is Q of a cavity resonator?

(2 marks) 00

1.j. Why the S-parameters used in microwave?

(3 marks) 00

PART-B

2.a. Discuss the significance and advantages if dominant mode in a rectangular waveguide.

(5 marks) 00

2.b. A rectangular waveguide with a width of 4cm and height if 2 cm is used to propagate an electromagnetic wave in the TE10 mode. Determine the wave impedance, phase velocity and group velocity of the waveguide for the wavelength of 6 cm.

(5 marks) 00

3.a. Distinguish between TE and TM modes of the propagation in a rectangular waveguide.

(6 marks) 00

3.b A wave of frequency 6Hz is propagated in a parallel plane waveguide separated by 3cm . Calculate i) the cut-off wavelength for the dominant mode. ii) wavelength in the waveguide iii) the group and phase velocities. iv) characteristics wave impedance.

(4 marks) 00

4.a. A 20 mV signal is fade to the series arm of lossless magic tee junction. Calculate the power delivered through each port when other ports are terminated with a matched load.

(4 marks) 00

4.b. Explain coupling probes and coupling loops.

(6 marks) 00

5.a. Explain the working of a two hole directional coupler with a neat diagram and derive the expression for the coupling and directivity of a two hole directional coupler.

(6 marks) 00

5.b. Fir a directional coupler, the incident power is 550 mW. Calculate the power in the main and auxiliary arm. The coupling factor is 30dB.

(4 marks) 00

6. Explain in detail bunching process and obtain expression for bunching parameter in a two cavity klystron.

(10 marks) 00

7.a. The parameter of a two cavity klystron given by Vb= 900V , f=3.2 GHz and d=10³. Determine electron velocity, transit angle and beam coupling coefficient.

(3 marks) 00

7.b. Explain the principles of a working of traveling wave tube.

(5 marks) 00

8.a. Derive the Hartree anode Voltage equation for Linear magnetron.

(6 marks) 00

8.b. A normal circular magnetron has the following parameters: inner radius 0.15 m , outer radius 0.45m , magnetic flux density 1.6 milli Weber/m² (i) determine Hull cut-off voltage. (ii) determine the Hull cut-off magnetic flux density if the beam voltage is 4000V.

(4 marks) 00

9.a. Explain Gunn Effect using two-valley theory. Also explain serval modes of operation and application of Gunn diodes.

(6 marks) 00

9.b. Give the classification if solids state microwave devices.

(4 marks) 00

10.a. Find the S matrix fir a matched isolator having an insertion loss of 0.5 dB. And isolation of 25dB.

(4 marks) 00

10.b. Explain the S-matrix representation of a multiport microwave network and its significance.

(6 marks) 00

11.a. Describe the block of microwave bench and their features.

(7 marks) 00

11.b. Calculate the VSWR of a transmission system operating at 15GHz TE modes is propagating through the waveguide of dimensions 4.0 and 2.1 cm respectively. The distance between two successive minima is 1.5 cm.

(3 marks) 00

ADD COMMENT EDIT