VASAVI COLLEGE OF ENGINEERING (Autonomous), HYDERABAD

B.E. (ECE) VI Semester (Main) Examinations, May-2018

Microwave Engineering

Max. Marks: 70

Time: 3 hours

Note: Answer ALL questions in Part-A and any FIVE from Part-B

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Part-A (10 x 2 = 20 Marks)

1. Define Standing Wave Ratio (SWR). What are its maximum and minimum values?
2. Explain the concept of impedance matching.
3. What is a magic tee? Mention its applications.
4. Write short notes on ferrite devices.
5. What are the advantages and disadvantages of microwave frequencies?

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6. Define transit time in a vacuum tube.
7. What are the limitations of conventional tubes at microwave frequencies?
8. Explain the working principle of a parametric amplifier.
9. Define frequency pulling and frequency pushing.
10. Write short notes on the applications of Gunn diode.

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Part-B (5 x 10 = 50 Marks)

1. 1. Derive the expressions for reflection coefficient and transmission coefficient in terms of characteristic impedance and load impedance.
   2. Explain different types of waveguide couplings.
2. 1. Explain the working of E-plane tee and H-plane tee with neat diagrams.
   2. What are the applications of isolators and circulators? Explain in detail.

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3. 1. Derive the wave equations for rectangular waveguides.
   2. Explain different types of losses in microstrip lines.
4. 1. Explain the construction and working of a two-cavity klystron amplifier with a neat sketch.

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   2. Explain the working principle of Reflex klystron oscillator.
5. 1. Explain the working of Tunnel diode with neat energy band diagrams.
   2. Explain the construction and working of IMPATT diode.

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6. 1. Explain the working principle of a TRAPATT diode.
   2. Write short notes on MESFETs.
7. 1. Describe the procedure for measuring impedance using a slotted line.
   2. Explain the measurement of microwave power using a Bolometer.

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